Aluminum nitride sintered body and process for producing the same

An aluminum nitride sintered body comprising aluminum nitride as a main component, and a titanium compound selected from the group consisting of Ti.sub.n O.sub.2n-1, a solid solution comprising Ti.sub.n O.sub.2n-1 and nitrogen partly dissolved therein, and TiN.sub.x O.sub.y wherein 0<x<1, y is 3/2 (1-x), and n is at least 1,

• said sintered body having a black color, a linear transmittance of not more then 10% for light having a wavelength of 500 to 650 nm and for light having a wavelength of 6 .mu.m, and a heat conductivity of at least 120 W/m.multidot.K, based on a sample thickness of 0.5 mm, wherein said aluminum nitride sintered body is produced by adding a sintering aid and 0.05 to 5.0%, by weight, in terms of Ti, of a titanium compound having a maximum primary particle diameter of 500 nm, to an aluminum nitride powder to form a mixture, wherein said aluminum nitride displays an absorption peak in infrared absorption analysis at 750 cm.sup.-1 or less,
• molding said mixture to form a shape,
• heating said shape in a vacuum, air, nitrogen, hydrogen, or an atmosphere comprising a combination of at least two of air, nitrogen, and hydrogen, until a residual carbon content is reduced to 0.2% by weight or less, thereby forming a product,
• and sintering the product in a non-oxidizing atmosphere containing nitrogen and a maximum CO concentration of 200 ppm at at least 1600.degree. C.

An aluminum nitride sintered body comprising aluminum nitride as a main component, and a titanium compound selected from the group consisting of Ti.sub.n O.sub.2n-1, a solid solution comprising Ti.sub.n O.sub.2n-1 and nitrogen partly dissolved therein, and TiN.sub.x O.sub.y wherein 0<x<1, y is 3/2 (1-x), and n is at least 1,

• said sintered body having a black color, a linear transmittance of not more than 10% for light having a wavelength of 500 to 650 nm and for light having a wavelength of 6 .mu.m, and a heat conductivity of at least 120 W/m.multidot.K, based on a sample thickness of 0.5 mm, wherein said aluminum nitride sintered body is produced by adding a sintering aid and 0.05 to 5.0%, by weight, in terms of Ti, of a titanium compound having a primary maximum particle diameter of 500 nm, and a compound capable of forming carbon after being thermally decomposed, to an aluminum nitride powder, wherein said aluminum nitride displays an absorption peak in infrared absorption analysis at 750 cm.sup.-1, or less, to form a mixture,
• molding said mixture to form a shape,
• heating said shape in a vacuum, air, nitrogen, hydrogen, or an atmosphere comprising a combination of at least two of air, nitrogen, and hydrogen, until a residual carbon content is reduced to 0.2% to 2.0% by weight, thereby forming a product, and
• sintering the product in a non-oxidizing atmosphere containing nitrogen and a maximum CO concentration of 200 ppm at at least 1600.degree. C.