The shear test in accordance with DIN EN 15.340 is a method to test the bond between substrate and coating in thermal spraying. It has been developed in order to avoid the disadvantages of the test mainly in use, the adhesion test (DIN EN 582). In quality management in a thermal spraying job shop often results of coating analyses are necessary within a very limited time frame; very important is a low number of necessary specimens and a fast and reliable test method. It is described how the shear test can be implemented into the practice of a job shop and the experiences of the OBZ innovation GMBH, which has used the shear test for more than four years, are explained.

The shear test in accordance with EN 15340 is a new test method for testing the bond between substrate and thermally sprayed coatings. It has been developed in order to enable a test method without the disadvantages of the method currently in use, the adhesion test. In the adhesion test the adhesives influence the test results; therefore in the shear test no adhesives are used. The adhesives are among others the reason for a large deviation of the test results using the pull-off test. Using the shear test the mode of the test results depend on the ratio between adhesion and cohesion; this ratio causes three different fracture modes. In order to investigate the deviation depending on the fracture mode samples have been coated by wire flame spraying, arc, plasma and HVOF spraying. Different ceramics, carbides and metals have been used as thermal spraying materials. For each material-process combination between 30 and 120 samples have been coated. This report describes the interpretation of the results of the shear test depending on the fracture mode and the coating materials applied by different thermal spraying processes. The deviation of the results depending on the fracture mode has been investigated using a shear test device by which the shear force is recorded over the displacement of the coating. The knowledge of the deviation and the distribution of the results is necessary to decide on the required number of samples to reach a result with a defined reliability.

Anilox rolls are ink-metering rolls used in the printing industry to transfer an exact amount of ink to the printing cylinder. The importance of high quality anilox rolls has increased with the demand for higher quality printing. Improvements of the characteristics of anilox rolls have been achieved mainly by using laser-engraved, ceramic-coated rolls rather than the common chrome-plated and mechanically engraved rolls. The best results concerning the ceramic coating of anilox rolls were achieved by Cr 2 O 3 coatings. These coatings require a bond coat for good corrosion resistance. By far the most-used technology to produce this bond coat is high velocity oxygen fuel (HVOF) spraying using NiCr material. In order to lower the cost of the anilox roll coating it has been investigated if NiCr can be replaced by the chromium steel 316L as bondcoat material. 316L was applied to the surface by HVOF. The characteristics of 316L / Cr 2 O 3 layers were compared with respect to the required quality of the coating. The results were 316L / Cr 2 O 3 coatings with good mechanical characteristics compared to NiCr / Cr 2 O 3 layers. In particular, the metallographic sections showed compact coatings having a tensile adhesive strength slightly higher than and a corrosion resistance similar to the coatings with a NiCr bond coat.

This article gives an overview of thermal spraying of polymers with respect to the different spraying processes, the polymer materials in use for thermal spraying and new trends of using polymers as separate spraying material and in combination with plastic and non-plastic materials. Flame spraying is by far the most common process used for thermal spraying of plastic materials. In addition in the past years two other processes have been used to produce thermal sprayed plastic coatings: plasma spraying and high-velocity oxy fuel spraying (HVOF). The areas where the different processes are used as well as the modifications to conventional plasma and HVOF devices and the advantages and disadvantages using these two processes to produce plastic coatings will be described. In addition to the common materials used for flame spraying (e.g., PA 11, PA 12 or EVAL), other materials giving new opportunities of application of thermal sprayed coatings have been used like PEEK and LCPs. The areas where these materials are used are described as well as the special features of these materials. Furthermore there are new trends in using plastic materials for thermal spraying. Thermal sprayed polymer materials are for example combined with plastic as well as non-plastic materials or pigments giving special effects to the coatings, e.g, reflective or anti-skidding coatings. It is described how coatings with the mentioned effects can be produced.