Wear-resistant metal/ceramic powder for thermal spraying.(Coating)

A research group from a Spanish university and a public research body affiliated to the Spanish Ministry of Science and Technology has developed a new composite ceramic/metallic powder for thermal spraying. The powder is said to result in thermal-sprayed surface coatings with high resistances to wear and corrosion.

The material is obtained by self-propagating high-temperature synthesis.

The metallic phase is selected from stainless steel, plain steel, and intermetallics of titanium and/or nickel and/or aluminium. The ceramic phase is selected from titanium carbide (TiC), titanium diboride (Ti[B.sub.2]) or mixtures of the two.

According to its developers, the composite powder features a homogeneous distribution of ceramic and metallic particles and good chemical compatibility. The powder is suitable for processing using the following thermal spraying techniques:

* flame spraying; * atmospheric plasma spraying; * vacuum plasma spraying; * controlled atmosphere plasma spraying; * arc spraying; * detonation gun spraying; * high-velocity oxy-fuel spraying.

The preparation process for the composite powder comprises:

* mixing the metallic and ceramic components in a solvent carrier; drying the mixture;

* carrying out a self-propagating high-temperature reaction;

* milling and sieving the resultant composite powder to the desired particle size range.

The average particle size of the ceramic phase is important since its presence in the metallic phase can give rise to a substantial increase in certain properties, for example wear- and corrosion-resistance. The ideal ceramic powder has an average particle size of 0.1-5 gym, with the proportion of the ceramic phase between 20 and 80% by weight.

For further information, contact: Aina Roca, Centre d'Innovacio I Desenvolupament

Empresarial, Passeig de Gracia 129 4t, E-08008 Barcelona, Spain; tel +34-93-4767294; fax: +34-934-767215; E-mail: aroca@cidem.gencat.net; Internet: wwwcidem.com