A cBN sintered material comprising cBN particles and a binder phase, in which the binder phase contains AlN and AlB.sub.2, a content proportion of cBN particles is 70 to 97 vol %, cBN sintered material has a volume resistivity up to 5×10.sup.−3 Ωcm, a rate of a peak intensity derived from Al with respect to a peak intensity derived from cBN particles is less than 1.0%, cBN particles include fine particles and coarse particles, coarse particles optionally include ultra-coarse particles, with respect to the entire cBN particles, a content proportion α of fine particles is from 10 vol %, a content proportion β of coarse particles is from 30 vol %, a content proportion γ of ultra-coarse particles is 25 vol % or less, and a total of the content proportion α of fine particles and the content proportion β of coarse particles is 50 to 100 vol %.

A cBN sintered material comprising cBN particles and a binder phase, in which the binder phase contains AlN and AlB.sub.2, a content proportion of cBN particles is 70 to 97 vol %, cBN sintered material has a volume resistivity up to 5×10.sup.−3 Ωcm, a rate of a peak intensity derived from Al with respect to a peak intensity derived from cBN particles is less than 1.0%, cBN particles include fine particles and coarse particles, coarse particles optionally include ultra-coarse particles, with respect to the entire cBN particles, a content proportion α of fine particles is from 10 vol %, a content proportion β of coarse particles is from 30 vol %, a content proportion γ of ultra-coarse particles is 25 vol % or less, and a total of the content proportion α of fine particles and the content proportion β of coarse particles is 50 to 100 vol %.

Provided are a coating structure, a turbine part having the same, and a method for manufacturing the coating structure. The coating structure is provided on a surface of a base portion including a ceramic matrix composite. The coating structure is layered on the surface of the base portion, and includes a bond coat layer formed of a rare-earth silicate and a top coat layer layered on the bond coat layer. The residual stress present in the bond coat layer is compressive residual stress. The oxygen permeability coefficient of the bond coat layer is no greater than 10.sup.−9 kg.Math.m.sup.−1.Math.s.sup.−1 at a temperature of not lower than 1200° C. and a higher oxygen partial pressure of not less than 0.02 MPa. The bond coat layer may contain carbonitride particles or carbonitride whiskers.

Provided are a coating structure, a turbine part having the same, and a method for manufacturing the coating structure. The coating structure is provided on a surface of a base portion including a ceramic matrix composite. The coating structure is layered on the surface of the base portion, and includes a bond coat layer formed of a rare-earth silicate and a top coat layer layered on the bond coat layer. The residual stress present in the bond coat layer is compressive residual stress. The oxygen permeability coefficient of the bond coat layer is no greater than 10.sup.−9 kg.Math.m.sup.−1.Math.s.sup.−1 at a temperature of not lower than 1200° C. and a higher oxygen partial pressure of not less than 0.02 MPa. The bond coat layer may contain carbonitride particles or carbonitride whiskers.

A method includes forming a crystallized metal carbide undercoat on a surface of a carbon-carbon composite substrate. The method further includes forming an overcoat on a surface of the undercoat. The overcoat includes a plurality of crystallized ultra-high melting point overcoat layers. Each overcoat layer is sequentially formed by applying a mixture to a surface of an underlying layer and heating the mixture. The mixture includes a plurality of ultra-high melting point refractory ceramic particles and a pre-ceramic polymer. The mixture is heated to a heat treatment temperature to pyrolyze the pre-ceramic polymer and form the overcoat layer in an inert atmosphere or under vacuum. As a result, the overcoat layer includes a crystallized ultra-high melting point polymer-derived ceramic matrix that includes the plurality of ultra-high melting point refractory ceramic particles.

A method includes forming a crystallized metal carbide undercoat on a surface of a carbon-carbon composite substrate. The method further includes forming an overcoat on a surface of the undercoat. The overcoat includes a plurality of crystallized ultra-high melting point overcoat layers. Each overcoat layer is sequentially formed by applying a mixture to a surface of an underlying layer and heating the mixture. The mixture includes a plurality of ultra-high melting point refractory ceramic particles and a pre-ceramic polymer. The mixture is heated to a heat treatment temperature to pyrolyze the pre-ceramic polymer and form the overcoat layer in an inert atmosphere or under vacuum. As a result, the overcoat layer includes a crystallized ultra-high melting point polymer-derived ceramic matrix that includes the plurality of ultra-high melting point refractory ceramic particles.

A coated cutting tool comprising: a substrate and a coating layer, wherein the coating layer includes a lower layer and an upper layer; the lower layer includes one or two or more specific Ti compound layers; the upper layer includes an α-type Al.sub.2O.sub.3 layer; an average thickness of the lower layer is 2.0 μm to 15.0 μm; an average thickness of the upper layer is 3.5 μm to 15.0 μm; in the upper layer, a ratio of a length of Σ3 grain boundaries to a total length of 100% of a total grain boundary is more than 50% and 80% or less, and a ratio of the length of Σ3 grain boundaries to a total length of 100% of CSL grain boundaries is 70% or more; and in the upper layer, a texture coefficient TC(0,0,12) of the α-type Al.sub.2O.sub.3 layer is 8.0 or more and 8.9 or less.

Provided is a ceramic sintered body having high wear resistance and chipping resistance. Also provided are an insert, a cutting tool and a friction stir welding tool, each of which uses such a high-performance ceramic sintered body. The ceramic sintered body includes Al.sub.2O.sub.3 (alumina), WC (tungsten carbide) and ZrO.sub.2 (zirconia), wherein Zr (zirconium) element is present at either one or both of: (1) a grain boundary between crystal grains of the Al.sub.2O.sub.3; and (2) a grain boundary of crystal grains of the Al.sub.2O and crystal grains of the WC, wherein the ceramic sintered body contains 55.0 to 97.5 vol % of the WC, 0.1 to 18.0 vol % of the ZrO.sub.2, and the balance being the Al.sub.2O.sub.3, and wherein the ZrO.sub.2 is in a phase of tetragonal structure (T) or a mixed phase of tetragonal structure (T) and monoclinic structure (M).

A method of providing a self-healing coating includes providing substrate, applying a layer of an aluminum-containing MAX phase material and another material to the substrate. The method includes exposing the layer to a temperature greater than 2000° F. to form alpha aluminum.

A method of providing a self-healing coating includes providing substrate, applying a layer of an aluminum-containing MAX phase material and another material to the substrate. The method includes exposing the layer to a temperature greater than 2000° F. to form alpha aluminum.