Abstract: A process for forming a titanium carbonitride cemented carbide cutting insert, said cemented carbide is comprised of more than 70 percent by weight tungsten carbide and has a matrix binder comprising cobalt with a cobalt enriched stratified surface. The process comprises chemically vapor depositing a layer of titanium carbonitride on said cemented carbide substrate by heating gaseous reactants comprising titanium chloride, methane, hydrogen, and nitrogen with an optimum methane/nitrogen ratio, under suitable conditions to form a titanium carbonitride coated insert having an eta phase in the cemented carbide substrate adjacent said titanium carbonitride coating.

Abstract: The invention relates to a cemented carbide or ceramic article having a multilayered coating of a plurality of ultrathin CVD coating layers, and a process for producing same. Each of the ultrathin CVD coating layers has a thickness of approximately 200 nanometers or less. The multilayered coating ranges from approximately 50-400 layers, has excellent adherence and a smoothness and a hardness of at least approximately 40 GPa. The CVD coated article of the present invention exhibits improved coating properties of excellent smoothness, uniformity, toughness, hardness and abrasive wear resistance.

Abstract: A process for forming a titanium carbonitride coated stratified cobalt enriched cemented carbide cutting insert, said cemented carbide is comprised of more than 70 percent by weight tungsten carbide and has a matrix binder comprising cobalt with a cobalt enriched stratified surface. The process comprises chemically vapor depositing a layer of titanium carbonitride on said cemented carbide substrate by heating gaseous reactants comprising titanium chloride, methane, hydrogen, and nitrogen with an optimum methane/nitrogen ratio, under suitable conditions to form a titanium carbonitride coated insert having an eta phase in the cemented carbide substrate adjacent said titanium carbonitride coating. The eta phase comprises chemical compounds consisting essentially of cobalt, tungsten and carbon, and the titanium carbonitride surface is contacted with a carburizing gas for a sufficient time and at a sufficient temperature to convert substantially all of said eta phase to elemental cobalt and tungsten carbide.

Abstract: A process for forming a titanium carbonitride cemented carbide cutting insert, said cemented carbide is comprised of more than 70 percent by weight tungsten carbide and has a matrix binder comprising cobalt with a cobalt enriched stratified surface. The process comprises chemically vapor depositing a layer of titanium carbonitride on said cemented carbide substrate by heating gaseous reactants comprising titanium chloride, methane, hydrogen, and nitrogen with an optimum methane/nitrogen ratio, under suitable conditions to form a titanium carbonitride coated insert having an eta phase in the cemented carbide substrate adjacent said titanium carbonitride coating.

Abstract: A process for forming a titanium carbonitride coated stratified cobalt enriched cemented carbide cutting insert, said cemented carbide is comprised of more than 70 percent by weight tungsten carbide and has a matrix binder comprising cobalt with a cobalt enriched stratified surface. The process comprises chemically vapor depositing a layer of titanium carbonitride on said cemented carbide substrate by heating gaseous reactants comprising titanium chloride, methane, hydrogen, and nitrogen with an optimum methane/nitrogen ratio, under suitable conditions to form a titanium carbonitride coated insert having an eta phase in the cemented carbide substrate adjacent said titanium carbonitride coating. The eta phase comprises chemical compounds consisting essentially of cobalt, tungsten and carbon, and the titanium carbonitride surface is contacted with a carburizing gas for a sufficient time and at a sufficient temperature to convert substantially all of said eta phase to elemental cobalt and tungsten carbide.

Abstract: A densified composite comprises an aluminum oxide matrix reinforced with titanium carbide whiskers of a preferred structure which whiskers are produced according to a process by selecting particular reaction conditions.

Abstract: In a process for preparing a coated cemented carbide cutting insert, a layer of titanium carbide containing eta phase is first vapor deposited directly adjacent a cobalt cemented tungsten carbide substrate and the eta phase is then removed by contacting the titanium carbide surface with a carburizing gas under suitable conditions to convert the eta phase to elemental cobalt and tungsten carbide.