Ceramic functional layers with interesting properties

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Quelle/Source: Klaus Vollrath

1 Martin Bührer: ”Compared to metals, ceramics provide some very interesting advantages, such as high hardness, resistance to aggressive chemicals and corrosion and usually high temperature resistance”

Quelle/Source: Klaus Vollrath

2 Spray head mounted on a robot arm for atmospheric plasma spraying. The powder is fed from above to the centrally emitted plasma jet

Quelle/Source: Klaus Vollrath

3 The area of this shaft to be coated, which is intended for a new hydraulic engine, was turned while the other areas were protected by masking

Quelle/Source: Klaus Vollrath

4 Coating of new parts: Above, turned and masked before coating, below the finished Cr₂O₃ coating

Quelle/Source: Klaus Vollrath

5 Samples with different ceramic coatings: Above, aluminum oxide Al₂O₃, in the middle chromium oxide Cr₂O₃ and below titanium oxide TiO₂

Quelle/Source: Klaus Vollrath

Quelle/Source: Bührer AG

6 In interaction with the robot control, the system’s NC ensures high consistency and reproducibility. Parameters that have once been saved can be exactly reproduced

Quelle/Source: Bührer AG

Quelle/Source: Klaus Vollrath

7 For rotational parts, the cabin is provided with an additional numerically controlled axis of rotation

Quelle/Source: Klaus Vollrath

8 Demonstrator component with sprayed-on coating ground to size and consisting of hard, chemically resistant and abrasion-resistant chromium oxide Cr₂O₃

Quelle/Source: Klaus Vollrath

Klaus Vollrath

9 Klaus Vollrath, Aarwangen/Schweiz

Klaus Vollrath

Summary: Designers in mechanical engineering would sometimes prefer metal components to have properties that are rather found in ceramics. In such case, surface coatings consisting of various ceramic materials could be a remedy, since they are characterized by high hardness, wear and corrosion resistance, chemical resistance, dielectric strength or good thermal isolation, as the case may be. The Bührer AG, a specialist in thermal spray coating, bets on a new system suitable for the application of such ceramic layers.

“Compared to metals, ceramics provide some very interesting advantages, such as high hardness and resistance to aggressive chemicals as well as to high temperatures”, explains Martin Bührer, owner of the Bührer AG with its headquarters in Otelfingen/Switzerland (Fig. 1). But on the other hand, they also have some disadvantages, in particular with regard to ductility, impact resilience or dynamic load capacity. Therefore, pure ceramic components are rather rarely used in mechanical engineering. Instead, from the designers’ point of view more interesting is the possibility to utilize the...