Ceramic materials intended for cutting and consisting of aluminum oxide with additives of hard carbides or nitrides, particularly titanium carbide, have up to now, because of their sintering inertia, in general been pressure sintered to obtain satisfactory properties. According to the present invention a ceramic alloy of excellent technological properties has been formed and comprises principally Al.sub.2 O.sub.3 and hard nitrides or carbonitrides, such as TiN or Ti(C,N) in which the alloy contains from 2 to 95 v/o of an Al--O--N-compound, such as nitrogen stabilized aluminum oxide with cubic or nearly cubic structure.
The present invention is characterized by ceramic materials comprising ceramic sintered bodies consisting of (1) 1-90 wt % chromium carbide and the remainder carbonic titanium nitride; (2) 1-90 wt % chromium carbide, 0.1-5 wt % B.sub.4 C and the remainder titanium carbo-nitride; or (3) either of the above compositions plus less than 95 wt % of a metal boride such as Ti or Zr. Such ceramic sintered bodies are used for cutting tools or wear-resistant machine parts because of their high density, high hardness and high strength.
The invention relates to a substrate made from a novel type of ceramic material. This material comprises 44-47 at. % A1, 31-39 at. % O, 8-13 at. % C and 8-12 at. % N. Substrates made from this material exhibit a relatively high heat conductance, a relatively great strength and their coefficient of expansion is equal to that of Si. Consequently, the substrates in accordance with the invention are very suitable for use in the Si-semiconductor technology. The main component of the ceramic material of the substrates preferably corresponds to the formula Al.sub.28 O.sub.21 C.sub.6 N.sub.6. The invention also provides methods of manufacturing substrates and other mouldings from this material.
A composite article and cutting tool are prepared by densification to form a body consisting essentially of particles of hard refractory material uniformly distributed in a matrix consisting essentially of a first phase and a second phase, said first phase consisting essentially of crystalline silicon nitride and said second phase being an intergranular refractory phase comprising silicon nitride and a suitable densification aid selected from the group consisting of yttrium oxide, zirconium oxide, hafnium oxide and the lanthanade rare earth oxides and mixture thereof.
The invention relates to a substrate made from a novel type of ceramic material. This material comprises 44-47 at. % Al, 31-39 at. % O, 8-13 at. % C and 8-12 at. % N. Substrates made from this material exhibit a relatively high heat conductance, a relatively great strength and their coefficient of expansion is equal to that of Si. Consequently, the substrates in accordance with the invention are very suitable for use in the Si-semiconductor technology. The main component of the ceramic material of the substrates preferably corresponds to the formula Al.sub.28 O.sub.21 C.sub.6 N.sub.6. The invention also provides methods of manufacturing substrates and other mouldings from this material.
A seat assembly particularly adapted for support upon the inclined side frame members of the Baker tree stand (U.S. Pat. No. 3,460,649). The seat assembly includes an elongated seat member transversely spanning the side frame members and being provided with depending legs resting upon the side frame members, and a pair of hanger straps affixed to the opposite ends of the seat member and projecting upward and rearward, and pin members selectively and detachably connecting the upper ends of the hangers members, behind the seat member, to a set of longitudinally spaced bolt holes in the side frame members.
