Abrasive particles based on aluminium oxynitride

Abstract

A plasma processing apparatus includes an evacuatable processing vessel; a workpiece mount base for mounting thereon an object to be processed; a microwave transmitting plate provided in an opening of a ceiling of the processing vessel; a planar antenna member for supplying a microwave into the processing vessel via the microwave transmitting plate; a shield lid grounded to cover a top of the planar antenna member; a waveguide for guiding the microwave to the planar antenna member; a member elevating mechanism for relatively varying a vertical distance between the planar antenna member and the shield lid; a tuning rod insertable into the waveguide; a tuning rod driving mechanism for moving the tuning rod to adjust an insert amount thereof; and a matching control section for controlling an elevation amount of the planar antenna member and the insert amount of the tuning rod to obtain a matching adjustment.

1 . Abrasive grains based on aluminium oxynitride, characterised by an equivalent content of AlN as measured on an Al 2 O 3 AlN pseudo-binary diagram equal to between 2.5% and 7.5% by weight, and a structure composed mainly of φ′ AlON and γ AlON.  
     
     
         2 . Abrasive grains according to  claim 1 , characterised by an equivalent content of AlN equal to between 3% and 6% by weight.  
     
     
         3 . Abrasive grains according to  claim 1 , characterised by a metal aluminium content of less than 0.3% by weight, and a free aluminium nitride content AlN of less than 0.3%.  
     
     
         4 . Abrasive grains according to  claim 3 , characterised by a metal aluminium content of less than 0.1% by weight, and a free aluminium nitride content AlN of less than 0.1%.  
     
     
         5 . Abrasive grains according to  claim 1 , further comprising titanium and/or chromium oxides at a total content of between 0.2% and 3.5% by weight.  
     
     
         6 . Abrasive grains according to  claim 5 , further comprising titanium and/or chromium oxides at a total content of between 2.5% and 3.5% by weight.  
     
     
         7 . Process for preparation of abrasive grains according to  claim 1 , including the preparation of an alumina content, or an aluminium nitride AlN and/or oxynitride Al X O Y N Z , this content being melted and cooled at less than 1° C. per minute.  
     
     
         8 . Process according to  claim 7 , characterised in that the content also includes titanium and/or chromium oxide.  
     
     
         9 . Process according to  claim 8 , characterised in that the titanium oxide is added to the content in the form of brown corundum containing from 1% to 4% TiO 2 .  
     
     
         10 . Process according to  claim 7 , characterised in that melting is done in a Higgins furnace without pouring.  
     
     
         11 . Process for preparation of abrasive grains according to  claim 1 , including the preparation of a mix of alumina, aluminium nitride AlN and/or oxynitride Al X O Y N Z  and possibly titanium oxide and/or chromium oxide powders, reactive sintering of this mix at a temperature of between 1950 and 2000° C., and cooling of the sintered grains at less than 1° C. per minute.  
     
     
         12 . Process according to  claim 11 , characterised in that the mix also contains chromium oxide and/or titanium oxide.  
     
     
         13 . Process according to  claim 12 , characterised in that the titanium oxide is added in the form of brown corundum containing from 1% to 4% of TiO 2 .  
     
     
         14 . Process according to  claim 7 , characterised in that it includes final washing of the grains with acid water with a pH of between 5 and 7.  
     
     
         15 . Abrasive grains prepared according to the process claimed in  claim 14 , characterised by an aluminium metal content less than 0.01% and a real content of aluminium nitride Al less than 0.01%.  
     
     
         16 . Abrasive grains according to  claim 1 , characterised by a hardness equal to or more than 16 GPa, and by a toughness equal to or more than 1.5 MPa{square root}m.  
     
     
         17 . An abrasive grinding wheel for grinding metals and metallic alloys, comprising abrasive grains according to  claim 1 .  
     
     
         18 . Abrasive cloth or paper support for polishing comprising abrasive grains according to  claim 1 .  
     
     
         19 . A polishing paste or spraying abrasive comprising abrasive grains according to  claim 1.