100 years of thermal spray: About the inventor Max Ulrich Schoop (2023)


RegisterSign in


  • Access throughyour institution

Article preview

  • Abstract
  • Section snippets
  • References (29)
  • Cited by (22)
  • Recommended articles (6)

Surface and Coatings Technology

Volume 220,

15 April 2013

, Pages 3-13

Author links open overlay panelStephanSiegmannaPersonEnvelopeChristophAbertb1Envelope


The Swiss inventor Max Ulrich Schoop is believed to be the “father” of thermal spray technology, as he submitted the first two patents in Germany and Switzerland for a metal spraying process delivering “dense metallic coatings” in the year 1909. This invention was based on the well known observation of his children shooting with Flobert guns in the garden, where the lead bullets formed splats when hitting the wall. But who was this Mr. Schoop?

Max Ulrich Schoop completed his basic school in Zurich and apprenticeship in graphic processes at the Kronenberg Institute in Allgäu (Germany). After that he returned to Switzerland as a photographer's assistant and later on as a portrait retoucher.

As his oldest brother Paul worked as a director of a factory for batteries, Schoop was sent to the Moscow branch, where he left due to health reasons and went to Nizhny–Novgorod as a French and piano teacher. When he returned to Zurich in 1895 he started to study Physics and Electrotechnology at the Technical University of Zurich. After that he went to Vienna and Cologne, back in the accumulator business. In the year 1903 he went to Paris, where he invented the welding of aluminium. In order to market his invention he travelled to the United States of America where he also met Thomas Alva Edison in the year 1907. Schoop then returned to Zurich and opened his own laboratory in the year 1910 to further develop the thermal spray technology for the next 35years. He finally died in Zurich on February 29, 1956 at the age of 85.

May this summary elucidate this brilliant person at the centenary of the first thermal spray patent application.

Section snippets

Stages of Schoop's life

The three villages Kesswil, Utwil and Dozwil in the Swiss region of Thurgau near Konstanz (Germany) once were Roman colonies. The “Scopius” family came from Dozwil; over the centuries Scopius changed into the name Schoop. According to a seventeenth century monastery chronicle, the ancestors worked as schoolmasters, pastors and farmers; especially many school teachers among them.

Max Ulrich Schoop was born at Frauenfeld on April 10, 1870, where his father was the schoolmaster. His father followed

Schoop visited Edison

Those, who visited Schoop in his laboratory at Zurich, could read at the front of the house: “Inventing means: 1% inspiration, 4% illusion, 95% transpiration!”. This was also Thomas Alva Edison's view.

It was on a bitterly cold morning in February 1907, when Schoop crossed the Hudson River in the Lakawanna Railroad ferry, arriving at West Orange after about an hour's cruise. A small, agile sleigh brought him to Llewellyn-Park, where Edison had moved his laboratories in 1887. In size, perfection

The invention of the metal spray process

The year 1909 brought the breakthrough for Max Ulrich Schoop, the invention or discovery of metal spraying.

For more than half a century processes are known which make it possible to disperse all kind of materials as varnish, paint or liquid metal by means of compressed air or steam. Therefore it is actually astonishing that this method was not refined to manufacture metal coatings long since. Also with this discovery, as it often happens, coincidence played a major role. As it may save or

Meeting Count Zeppelin

The popular count Zeppelin gave Schoop a friendly welcome. Indirectly through an American magazine, count Zeppelin had heard from Schoop's invention of aluminium welding and invited him by telegram to a demonstration in Friedrichshafen. “Hey you, young man” said Zeppelin, “for ten years I have been awaiting this invention!” Unfortunately the equipment Schoop had at his disposal for the demonstration was ridiculously primitive as it consisted in nothing more than a plumber's blowlamp. His

His last wish

As a Christian and an admirer of Tolstoy he should have regarded the love towards men as the highest of all virtues. On the other hand he loved the animals, the unprotected, oppressed animals. Often when Schoop met a dog strolling around, he stopped and asked: Where're you going? And if they had nothing to talk about he liked to look at him and tried to adapt to the thoughts in his interior. Also Schoop had always sugar in his pockets for his friends, the animals.

“When I'll set off on the long


This summary is based on the booklet “Max Ulrich Schoop — Aus dem Leben eines Schweizerischen Erfinders” published by Carl Seelig [19] and translated by F. Nordsieck. We are grateful to all people of the civil registry offices, registration offices, patent offices, news paper archives, and picture libraries, etc. who helped in finding the traces and additional data of Max Ulrich Schoop compiled in this article.

Interested readers in Max Ulrich Schoop's inventions may also be referred to the

References (29)

  • Joseph Sedelmayer et al.
  • French Patent Nr. FR374089 «Procédé de soudure autogène de l'aluminium»...
  • British Patent No. 24283 «Improvement in Welding or Melting Objects of Aluminium» 1908–11–02,...
  • US Patent No. US922523 «Flux for the autogenous welding of Aluminum»...
  • Matthew Josephson

    Thomas Alva Edison Biographie


  • M.U. Schoop: Verfahren zum Herstellen dichter, metallischer Überzüge, Patent-Nr. 258505, DE,...
  • M.U. Schoop: Verfahren zur Herstellung von dichten metallischen Schichten, Patent-Nr. 49278, CH,...
  • M.U. Schoop et al.

    Handbuch der Metallspritz-Technik


  • F. Neininger: Elektrisches Verfahren und Vorrichtung zum Metallspritzen, Patent-Nr. 80098, CH,...
  • from “Amriswiler Schreibmappe 1950”: Article “Dreimal Schoop” from C....
  • Cited by (22)

    • Thermal cyclic oxidation of NiCoCrAlYTa coatings manufactured by combustion flame spray

      2020, Materials Today Communications

      Cyclic oxidation tests of NiCoCrAlYTa coatings were carried out at temperatures of 1173 and 1273 K by 100 cycles. NiCoCrAlYTa coatings with initial microstructure formed by typical lamellar-splat were previously manufactured by combustion flame spray. A kinetic analysis revealed parabolic behaviour during oxidation of the NiCoCrAlYTa coatings. After oxidation treatment, scanning electron microscopy and x-ray diffraction analysis showed that alumina and Ni, Cr spinels oxides were formed in the coating. The NiCoCrAlYTa coatings obtained by CFS, shown to have important oxidation resistance at high-temperature.

    • Effect of cooling rate on residual stress and mechanical properties of laser remelted ceramic coating

      2018, Journal of the European Ceramic Society

      Citation Excerpt :

      Thermal spraying is a well-known surface modification technique utilized to deposit thick coatings on bulk substrates to modify their surface properties [6,7]. Flame spraying was the first thermal spray process developed [8]. In the powder flame spraying process, the powder feedstock is carried by a gas flow into the oxy-fuel flame, which heats and propels it towards the substrate.

      Mild steel substrates were coated with commercially available alumina and chromia powders using the powder flame spraying process. The top layers of the flame sprayed coatings were remelted using a 2 kW fiber laser. Thermo-cycles of the laser remelting process were monitored on-line using an infrared pyrometer. Cooling rates were varied using different laser scanning speeds. Surface morphology, microstructure and phases of the laser treated and as-sprayed coatings were investigated using optical microscopy, scanning electron microscopy, X-ray diffraction and X-ray tomography. Surface residual stress of the as-sprayed and laser treated coatings was measured using X-ray diffraction. The inherent defects like porosity and inter-lamellar boundary diminish to a great extent upon laser remelting. Surface residual stress of the remelted coatings tends to increase with increase in cooling rate. Surface crack density of the laser treated coating was reduced appreciably when coatings were preheated prior to laser remelting.

    • Characterisation of three-dimensional porosity in an Fe-based amorphous coating and its correlation with corrosion behaviour

      2015, Corrosion Science

      Citation Excerpt :

      Thermal sprayed coatings are frequently used to protect surfaces of metals and alloys against corrosion and wear, and have been widely used in industry [1–3].

      Porosity, an important and inevitable property of thermally sprayed coatings, considerably influences the corrosion resistance of the coated materials. In this work, the correlation between porosity and corrosion of an Fe-based amorphous coating was investigated. The volume fraction, size and distribution of the coating porosity were measured and analysed via 3D XRT technique. Direct evidence for preferential substrate corrosion caused by the through-porosity was obtained. It was found that through-porosity is sensitive to the coating thickness. The critical coating thickness for the presence of through-porosity was determined, which could provide a guide for the design of corrosion resistant coatings.

    • Thermal Spray Coating Processes

      2014, Comprehensive Materials Processing

      Thermal spraying includes a group of coating processes in which metallic and nonmetallic materials are spray deposited as fine particles in a molten or semimolten condition or even in fully solid state to form a coating. Thermal spraying allows deposition of coatings, from some tens of micrometers up to several millimeters in thickness. Thermally sprayed coatings are used in very different applications including protective and functional coatings in mechanical engineering, energy technology, biomedical, steel, automotive, aerospace, and many other industrial sectors. The present overview is a generic summary of the topic trying to comprehensively cover many important related aspects and to give to the reader a general knowledge about the technology, formation of the coatings, coating materials with their properties, and industrial applications of the coatings.

    • Cold Spray: Over 30 Years of Development Toward a Hot Future

      2022, Journal of Thermal Spray Technology

    View all citing articles on Scopus

    Recommended articles (6)

    • Research article

      Bioactivity and mechanical properties of plasma-sprayed coatings of bioglass powders

      Surface and Coatings Technology, Volume 220, 2013, pp. 60-66

      Bioactive glass powders were prepared from four different types of oxides (SiO2, P2O5, CaO and MgO). These oxides were mixed, melted and milled to produce two compositions of a 31SiO2–11P2O5–(58−x)CaO–xMgO system, where the values x=0 and x=2 describe powders P1 and P2, respectively. The powders were sieved to obtain a particle size distribution of 1.8–40μm for P1 and 13–59μm for P2. The thermal stability of the powders was determined by differential thermal analysis (DTA). The powders were plasma sprayed on AISI 316L stainless steel substrates using a F4MB Sulzer Metco gun. The plasma-forming gas was a mixture of Ar/H2 (47/8L/min), and the current intensity used was 650A. The microstructure of the powders and the obtained coatings was examined by SEM. X-ray diffraction (XRD) was used to identify the crystalline phases in the powders and coatings. The hardness of the coatings, their adhesion to the substrates and the residual stresses in them were determined by a Vickers micro-indentation test, tensile test (according to ASTM C633) and curvature method, respectively. The microhardness of the coatings was between 4.7 and 5.2GPa, their strength of adhesion to the substrate was between 2.73 and 4.42MPa and the compression residual stress generated during the thermal spraying process was between −11.9 and −27.3MPa. The bioactivity was determined by the dissolution and subsequent formation of a hydroxyapatite layer by contacting the coatings with simulated body fluid for 1 and 15days.

    • Research article

      Numerical study on the effect of nozzle dimension on particle distribution in cold spraying

      Surface and Coatings Technology, Volume 220, 2013, pp. 107-111

      The height of rectangular nozzle's exit, throat and powder injector is changed systematically while the nozzle expansion ratio remains constant in order to study their effects on the distribution and velocity of magnesium (Mg) particles using three-dimensional models of cold spraying system. The effect of particle size on the particle distribution is also studied. It is found that the particle distribution is mainly influenced by the turbulent kinetic energy of the carrier gas flow at the nozzle exit. Changing the height of the exit or throat can control the particle distribution. The height of powder injector only influences the particle velocity.

    • Research article

      Tribological properties of plasma and HVOF-sprayed NiCrBSi–Fe2O3 composite coatings

      Surface and Coatings Technology, Volume 220, 2013, pp. 282-289

      This paper presents the properties of plasma and HVOF thermally sprayed coatings obtained by blending the NiCrBSi and Fe2O3 powders. Although the blended powders differ in particle size, shape, and distribution, it is possible to obtain composite coatings with a NiCrBSi matrix containing iron oxides. Except for a different microstructure, plasma and HVOF coatings have a different phase composition. An addition of Fe2O3 powder in the mixture with NiCrBSi powder led to a significant increase in roughness of the coating sprayed both in a plasma and supersonic manner. The coefficient of friction, microhardness and roughness of the coatings was determined using an experimental design called PS/DS-P:24−1 program. The study shows that the HVOF-sprayed coatings had a lower coefficient of friction.

    • Research article

      Comparative investigation on HVOF sprayed carbide-based coatings

      Applied Surface Science, Volume 273, 2013, pp. 799-805

      In this work, WC-17Co, WC-10Co-4Cr, WC-12Co and Cr3C2-25NiCr coatings were deposited on stainless steel using WOKAStar-640 HVOF spraying system. Three WC-based coatings were studied and compared with a chromium carbide-based coating. The microstructure, porosity, micro-hardness, indentation fracture toughness and adhesion strength of the coatings were investigated. The wear test was done by using silica grits as abrasive medium using a load of 20N. The result shows that HVOF sprayed carbide-based coating possesses low porosity, high micro-hardness and high adhesion strength. Three WC-based coatings have higher micro-hardness and indentation fracture toughness compared to the Cr3C2-25NiCr coating. HVOF sprayed carbide coating has good wear resistance under 500°C. The decarburization of WC-based coating has great effect on coating wear resistance. In addition, WC-17Co coating has best wear resistance.

    • Research article

      The effect of frontal nozzle geometry and gas pressure on the steel coating properties obtained by wire arc spraying

      Surface and Coatings Technology, Volume 220, 2013, pp. 266-270

      Wire arc spraying arc is a deposition procedure in which coating characteristics can be controlled by optimizing the spraying nozzle geometry or the process parameters. This paper presents the effect of spraying nozzle geometry (and dynamic of gases) on the properties of steel coatings. For this purpose, a spraying gun in electric arc with two wires was used, provided with a frontal and an axial nozzle. The frontal nozzle had different inclination angles of inner surface in order to generate a convergent–divergent geometry of gaseous fluid jet. The axial nozzle enabled the atomization and the acceleration of particles melted in electric arc towards substrate surface. The computational fluid dynamics (CFD) analyses of gaseous fluid dynamics, performed using continuity equation and the moment equation for different inclination angles of frontal spraying nozzle, led to the determination, inside the spraying jet, of a high speed zone (HSZ). The experimental results, obtained by the determination of particles velocities, of the coating porosity and by micrographic and SEM (scanning electron microscopy) analyses of the coating, demonstrated that HSZ influenced the velocity and the temperature of sprayed particles and implicitly the coating quality. So, for inclination angles of the inner surface more than the inclination angle of the wires, the air jet is convergent at the electric arc level and the resulting HSZ compressed the arc, causing increases both of current density and melting temperature of the material. In this case, the obtained coatings are fine, characterized by a reduced porosity due to the high velocity and temperature of sprayed particles. For inclination angles of inner surface lower than the inclination angles of wires, HSZ is formed in front of the electric arc, causing the decrease of particles temperature and velocity, thus altering coating properties.

    • Research article

      Design of next generation thermal barrier coatings — Experiments and modelling

      Surface and Coatings Technology, Volume 220, 2013, pp. 20-26

      Thermal barrier coating (TBC) systems have been used in the gas turbine industry since the 1980s. The future needs both the air and land based turbine industry involve higher operating temperatures with longer lifetime on the component so as to increase power and efficiency of gas turbines. The aim of this study was to meet these future needs by further development of zirconia coatings. The intention was to design a coating system which could be implemented in industry within the next 3years. Different morphologies of ceramic topcoat were evaluated; using dual layer systems and polymers to generate porosity. Dysprosia stabilised zirconia was also included in this study as a topcoat material along with the state-of-the-art yttria stabilised zirconia (YSZ). High purity powders were selected in this work. Microstructure was assessed with scanning electron microscope and an in-house developed image analysis routine was used to characterise porosity content. Evaluations were carried out using the laser flash technique to measure thermal conductivity. Lifetime was assessed using thermo-cyclic fatigue testing. Finite element analysis was utilised to evaluate thermal–mechanical material behaviour and to design the morphology of the coating with the help of an artificial coating morphology generator through establishment of relationships between microstructure, thermal conductivity and stiffness. It was shown that the combined empirical and numerical approach is an effective tool for developing high performance coatings. The results show that large globular pores and connected cracks inherited within the coating microstructure result in a coating with best performance. A low thermal conductivity coating with twice the lifetime compared to the industrial standard today was fabricated in this work.


    Tel.: +41 61 317 84 13; fax: +41 61 317 84 80.

    View full text

    Copyright © 2012 Elsevier B.V. All rights reserved.


    Who invented spray welding? ›

    The metal spraying industry has its beginnings early in the 20th century when Dr. M.U. Schoop of Zurich, Switzerland, developed the first process for spraying metal and, subsequently, the first equipment to spray metal in wire form.

    What is thermal spray method? ›

    Thermal spraying is a technology which improves or restores the surface of a solid material. The process can be used to apply coatings to a wide range of materials and components, to provide resistance to: Wear, erosion, cavitation, corrosion, abrasion or heat.

    Who invented thermal spray? ›

    The Swiss inventor Max Ulrich Schoop is believed to be the “father” of thermal spray technology, as he submitted the first two patents in Germany and Switzerland for a metal spraying process delivering “dense metallic coatings” in the year 1909.

    What is thermal spray welding? ›

    Spray welding is a term used to classify several welding procedures in the form of thermal spraying. It is an industrial activity that involves atomizing and spraying a powder or wire onto a metal surface at a high velocity with compressed gas.

    Where is thermal spraying used? ›

    Thermal spray coatings are extensively used in the manufacturing of gas turbines, diesel engines, bearings, journals, pumps, compressors and oil field equipment, as well as coating medical implants.

    What are the applications of thermal spray coating? ›

    In addition to original equipment applications, thermal spray coatings are used to repair parts worn and damaged in service, and restore dimensions to machined parts. Thermal spray coatings are used to restore the dimensions of components that have been worn or corroded, such as printing rolls and undersized bearings.

    What materials can be thermal sprayed? ›

    Thermal Spray is a range of high-performance ceramic, cermet and metallic coatings that can be applied to a range of steel, titanium, aluminium, and copper alloys, as well as to some non-metallic substrates.

    How does flame spray work? ›

    Flame spraying uses the heat from the combustion of a fuel gas, usually acetylene or propane with oxygen, to melt the spray coating material. In this process a consumable, usually a powder or wire, is heated and propelled onto a substrate to form a surface coating.

    How does spray coating work? ›

    The Plasma Spray Coating Process

    The material is rapidly heated and then accelerated toward the substrate. Once it reaches the surface, it begins to cool, forming a hard coating on the substrate and adding value to your final and finished product, component, or assembly.

    Which thermal spraying process creates the strongest bond? ›

    The High Velocity Oxygen Fuel (HVOF) thermal spray system produces coating with the strongest bond and highest hardness compared to any other thermal spray process.

    What is spray welding used for? ›

    Spray arc welding is one of the processes used to transfer metal from the electrode or wire to the weld. Minute molten droplets of metal travel via the arc and on to the base metal or the joint being worked on. Spray Transfer is ideal for use on thicker metals for butt or fillet joints.

    What is thermal spray Aluminum? ›

    Thermal Spray Aluminum (TSA) is a durable coating capable of providing complete corrosion protection and significant lifetime improvement for equipment.

    › topics › materials-science ›

    Thermal Spray - an overview

    https://www.sciencedirect.com › topics › materials-science
    https://www.sciencedirect.com › topics › materials-science
    Thermal spray technology is a coating process that provides functional surfaces to protect or improve the performance of a substrate or component. Thermal spray...
    Thermal spraying is a generic category of coating processes that apply a consumable as a spray of finely divided molten or semi-molten droplets to produce a coa...
    Spray welding is a term used to classify several welding procedures in the form of thermal spraying. It is an industrial activity that involves.

    What is spray welding used for? ›

    Spray arc welding is one of the processes used to transfer metal from the electrode or wire to the weld. Minute molten droplets of metal travel via the arc and on to the base metal or the joint being worked on. Spray Transfer is ideal for use on thicker metals for butt or fillet joints.

    What's the difference between pulse and spray welding? ›

    Pulsed MIG welding will typically see an increase in wire feed speed to match welding amperage when compared to standard spray transfer. This results in more weld metal going into the joint, which can increase productivity in the welding operation.

    What is powder spray welding? ›

    Hardfacing or surface coating is a process of spraying or welding metallic powders onto a workpiece or substrate to give it a specific hardness, wear resistance, or corrosion resistance.

    What gas is used for spray arc welding? ›

    The shielding gas must be pure argon, preferably with a small proportion of CO2 (not more than 25 %) or O2. Spray arc welding is particularly suitable for MIG welding of aluminium and stainless steel, for which the shielding gas is mainly argon.

    How hot is spray welding? ›

    The process operates at over 10,000C, which is hotter than the melting point for metals. The powder is injected into the flame, melted, and moved to the material being sprayed.

    Can you spray weld aluminum? ›

    Spray Weld Preparations

    We use two types of spray weld systems: Twin Arc System and the Flame Spray System. We can apply several types materials, 95% pure aluminum, aluminum bronze, cast iron and a 95% nickle 5% aluminum mixture. There are many other types materials we can apply if need.

    What voltage is spray transfer? ›

    For higher production speeds use spray transfer. Greater than 80% argon mix set the voltage at 23-4 volts to begin. Set the amperage with about 300-400 inches of wire feed speed.

    Is pulsed MIG worth the money? ›

    Pulsed MIG welding provides faster travel speeds, reduced spatter levels and improved control over arc starts compared to CV MIG, making it a good option for fabricators that want to boost efficiencies or improve weld quality.

    How do you stop a MIG welder from burning? ›

    Maintain a moderate arc length: Keep it constant at the recommended length (equal to the diameter of the electrode). Anything over or under, and you start to see burn-through. Use a shallow travel angle: Try not to hold the electrode vertical when welding; maintain the proper inclination for the entire joint.

    What to spray after welding? ›

    Thermal Spray Process

    Thermal spraying of zinc will completely restore the corrosion resistance of galvanized tube where welding has burned the zinc off the surface of the tube and where the weld metal is exposed.

    What is plasma spray coating? ›

    Plasma spraying is a coating process in which powders of the coating materials are fed into the plasma jet at around 10 000K, at which the coating materials melt and are sprayed over the substrate to be coated.

    How do you use a welding spatter spray? ›

    When using a spray application, shake the can as directed on the back of the product, then spray a light coating over your welding project and work area to prevent the bbs from sticking to the surface. The water solvent formula will make cleanup much faster and easier.

    Can you spray 100% argon transfer? ›

    Each mode pairs better with certain shielding gases. For example, you should never use 100 percent argon with a spray transfer mode. Instead, use a mixture such as 90 percent argon and 10 percent carbon dioxide.

    What is the best shielding gas for spray transfer? ›

    98/2 is an ideal gas for spray transfer. So those who weld exclusively on thicker stainless steel may benefit as much from helium mixes, and can save money by using 98/2.. After selecting a process and material type, then weighing the importance of each factor, it's time to choose a shielding gas.

    Can you use straight argon for MIG welding steel? ›

    Can You MIG Weld Steel Using 100% Argon Gas? It's a question every welder will face at some point, and yes, you can MIG weld steel if all you have is pure Argon.

    Top Articles
    Latest Posts
    Article information

    Author: Merrill Bechtelar CPA

    Last Updated: 01/25/2023

    Views: 5469

    Rating: 5 / 5 (50 voted)

    Reviews: 89% of readers found this page helpful

    Author information

    Name: Merrill Bechtelar CPA

    Birthday: 1996-05-19

    Address: Apt. 114 873 White Lodge, Libbyfurt, CA 93006

    Phone: +5983010455207

    Job: Legacy Representative

    Hobby: Blacksmithing, Urban exploration, Sudoku, Slacklining, Creative writing, Community, Letterboxing

    Introduction: My name is Merrill Bechtelar CPA, I am a clean, agreeable, glorious, magnificent, witty, enchanting, comfortable person who loves writing and wants to share my knowledge and understanding with you.