A surface-coated cutting tool includes a substrate and a coating formed on a surface of the substrate, the coating including one or two or more layers, at least one of the layers being an Al-rich layer including hard particles, the hard particle having a sodium chloride type crystal structure, and including a first unit phase in a form of a plurality of lumps and a second unit phase interposed between the lumps of the first unit phase, the first unit phase being composed of a nitride or carbonitride of Al.sub.xTi.sub.1-x, the first unit phase having an atomic ratio x of Al of 0.7 or more and 0.96 or less, the second unit phase being composed of a nitride or carbonitride of Al.sub.yTi.sub.1-y, the second unit phase having an atomic ratio y of Al exceeding 0.5 and less than 0.7.

A surface-coated cutting tool includes a substrate and a coating formed on a surface of the substrate, the coating including one or two or more layers, at least one of the layers being an Al-rich layer including hard particles, the hard particle having a sodium chloride type crystal structure, and including a first unit phase in a form of a plurality of lumps and a second unit phase interposed between the lumps of the first unit phase, the first unit phase being composed of a nitride or carbonitride of Al.sub.xTi.sub.1-x, the first unit phase having an atomic ratio x of Al of 0.7 or more and 0.96 or less, the second unit phase being composed of a nitride or carbonitride of Al.sub.yTi.sub.1-y, the second unit phase having an atomic ratio y of Al exceeding 0.5 and less than 0.7.

A cutting tool includes a base material. The base material is a cemented carbide or a cermet. A surface of the base material includes a rake face, a flank face, and a cutting edge face connecting the rake face to the flank face. The base material has an oxygen concentration of less than or equal to 1 at. % at a depth position of 0.4 μm from the cutting edge face.

A cutting tool includes a base material. The base material is a cemented carbide or a cermet. A surface of the base material includes a rake face, a flank face, and a cutting edge face connecting the rake face to the flank face. The base material has an oxygen concentration of less than or equal to 1 at. % at a depth position of 0.4 μm from the cutting edge face.

A surface-coated cutting tool includes a substrate and a coating formed on a surface of the substrate, the coating including one or two or more layers, at least one of the layers being an Al-rich layer including hard particles, the hard particle having a sodium chloride type crystal structure, and including a first unit phase in a form of a plurality of lumps and a second unit phase interposed between the lumps of the first unit phase, the first unit phase being composed of a nitride or carbonitride of Al.sub.xTi.sub.1-x, the first unit phase having an atomic ratio x of Al of 0.7 or more and 0.96 or less, the second unit phase being composed of a nitride or carbonitride of Al.sub.yTi.sub.1-y, the second unit phase having an atomic ratio y of Al exceeding 0.5 and less than 0.7.

A surface-coated cutting tool includes a base material and a coating formed on the base material. The base material is a cemented carbide or a cermet. A surface of the base material includes a rake face, a flank face, and a cutting edge face connecting the rake face to the flank face. The base material has an oxygen concentration of less than or equal to 1 at. % at a depth position of 0.4 μm from the cutting edge face. The coating includes a hard layer. A topmost layer in the hard layer has a compressive stress of more than or equal to 1.5 GPa in absolute value.

A surface-coated cutting tool includes a base material and a coating formed on the base material. The base material is a cemented carbide or a cermet. A surface of the base material includes a rake face, a flank face, and a cutting edge face connecting the rake face to the flank face. The base material has an oxygen concentration of less than or equal to 1 at. % at a depth position of 0.4 μm from the cutting edge face. The coating includes a hard layer. A topmost layer in the hard layer has a compressive stress of more than or equal to 1.5 GPa in absolute value.

A surface-coated cutting tool has a rake face and a flank face, and includes a base material and a coating formed on the base material. The base material has a cutting edge face connecting the rake face to the flank face. The coating includes an aluminum oxide layer containing a plurality of aluminum oxide crystal grains. The aluminum oxide layer includes: a first region made up of a region A on the rake face and a region B on the flank face; a second region on the rake face except for the region A; and a third region on the flank face except for the region B. The aluminum oxide layer satisfies a relation: b−a>0.5, where a is an average value of TC(006) in the first region in texture coefficient TC(hkl), and b is an average value of TC(006) in the second or third region in texture coefficient TC(hkl).

A surface-coated cutting tool includes a substrate and a coating that is disposed on the substrate and formed so as to cover at least a portion of a flank face, in which the coating includes an inner layer and an outer layer formed on the inner layer, the inner layer is formed of at least one layer and includes an aluminum oxide layer as a layer in contact with the outer layer, the outer layer has a multilayer structure that includes three or more layers stacked on top of one another, and each of the layers that constitute the multilayer structure contains titanium.

A surface-coated cutting tool includes a substrate and a coating that is disposed on the substrate and formed so as to cover at least a portion of a flank face, in which the coating includes an inner layer and an outer layer formed on the inner layer, the inner layer is formed of at least one layer and includes an aluminum oxide layer as a layer in contact with the outer layer, the outer layer has a multilayer structure that includes three or more layers stacked on top of one another, and each of the layers that constitute the multilayer structure contains titanium.