Abstract: The present invention relates to a method for coating a cutting insert having at least one layer of a carbide, carbonitride, oxynitride, oxycarbide, oxycarbonitride or nitride of one metal selected form the groups IVB, VB or VIB of the Periodic Table, the method comprising subjecting the insert to chemical vapor deposition and coating the insert with an epitaxial kappa-Al.sub.2 O.sub.3 layer by the hydrolysis reaction of AlCl.sub.3, H.sub.2 and CO.sub.2, the hydrolysis reaction being carried out while maintaining the content of water vapor in the gas phase during nucleation of Al.sub.2 O.sub.3 at less than 5 ppm.

Abstract: A coated body consisting of a substrate that can be decarburized during a carbide, nitride or carbonitride coating process comprising a first (innermost) carbon diffusion retarding coating of MetCO, MetCON, MetON adjacent to the substrate and a second (next innermost) wear resistant coating of MetC, MetN and/or MetCN, where Met is Ti, Hf, V, Zr, Si, B or other metals of subgroup 3-7 of the periodic table of the elements, or a mixture thereof. The intermediate coating has been found beneficial in order to reduce or even eliminate the formation of eta phase in the substrate.

Abstract: The present invention relates to a body coated with at least one double layer Al.sub.2 O.sub.3 -TiC. Because the Al.sub.2 O.sub.3 -layer in contact with the TiC-layer consists of kappa-Al.sub.2 O.sub.3 or theta-Al.sub.2 O.sub.3 an improved adherence has been obtained.A further improvement of the properties is obtained if the body after the coating is heat treated for 0.3-10 hours at 900.degree.-1100.degree. C. in protecting gas atmosphere at which initially nucleated kappa- or theta-Al.sub.2 O.sub.3 is transformed to fine grained alpha-Al.sub.2 O.sub.3.

Abstract: The wear resistance and toughness of a coated ceramic insert comprising a ceramic substrate and at least one thin surface layer of ceramic oxide is improved by applying at least one thin intermediate layer of hard borides of the subgroups or of the III-V groups of the periodic table, or of hard yttrium compounds. The layers are deposited from a gaseous phase.

Abstract: In coating cemented carbide or ceramics, with thin, wear resistant layers of ceramic oxide, particularly aluminum oxide, by CVD, it has been very difficult to make sufficiently even layers and to obtain desired thickness of the layer within reasonable coating times. According to the invention an improved method utilizing a dopant selected from the group consisting of sulfur, selenium, tellurium, phosphorous, arsenic, antimony, bismuth and mixtures thereof, is now available by which a considerable increase of the growth rate of the layer as well as optimal properties regarding evenness and thickness of the layer have been obtained, making the product better suited for cutting operation.

Abstract: A sintered hard metal body composed of at least one carbide as tungsten carbide and a binder phase consisting essentially of cobalt and/or nickel, the hard metal body being provided with a boronized surface zone having a thickness of 1-100 .mu.m characterized in that the hard metal contains small additions of up to about 5 percent by volume of the hard metal body of cubic carbides as VC, TiC, TaC, Mo.sub.2 C, ZrC, NbC and/or Cr.sub.3 C.sub.2, the content of binder phase is 6-40% of the volume of the body, and the mean grain size of the tungsten carbide is 0.2-1.5 .mu.m. The process of forming said body is also disclosed.

Abstract: An improved sintered cemented carbide body and method for making same is disclosed. The improved sintered cemented carbide body contains at least one metal carbide and a binder metal, on which body there is applied at least one thin, wear resistant surface layer consisting essentially of aluminum oxide and is characterized in that at least 85% of the aluminum oxide consists of the kappa form, the remainder, which mainly constitutes the alpha form, being formed as surface portions or spots having a size of at the most 10 .mu.m, the size and the occurrence of the surface portions being so adjusted that they lie within the area AOB in FIG. 1 of the attached drawing.The body is made by a method wherein a cemented carbide substrate is contacted with a gas containing an aluminum halide and a reducing agent at high temperature, characterized in that a dopant addition of tetravalent titanium, zirconium and/or hafnium ions is added to the gas in an amount of 0.03-0.5% of the totally supplied amount of gas.

Abstract: An improved sintered cemented carbide body and method for making same is disclosed. The improved sintered cemented carbide body contains at least one metal carbide and a binder metal, on which body there is applied at least one thin, wear resistant surface layer consisting essentially of aluminum oxide and is characterized in that at least 85% of the aluminum oxide consists of the kappa form, the remainder, which mainly constitutes the alpha form, being formed as surface portions or spots having a size of at the most 10 .mu.m, .[.the size and the occurrence of the surface portions being so adjusted that they lie within the area AOB in FIG. 1 of the attached drawing..].The body is made by a method wherein a cemented carbide substrate is contacted with a gas containing an aluminum halide and a reducing agent at high temperature, characterized in that a dopant addition of tetravalent titanium, zirconium and/or hafnium ions is added to the gas in an amount of 0.03-0.5% of the totally supplied amount of gas.