1. A method of producing an ultrahard abrasive composite material having a desirable overall thermal expansion coefficient mismatch, includes the steps of:
(a) providing a volume fraction of ultrahard particles having a pre-determined thermal expansion coefficient;
(b) determining the volume fraction and thermal expansion coefficient of a matrix material that would be required to produce an ultrahard composite material having a desired overall thermal expansion coefficient mismatch;
(c) selecting a matrix material having the determined thermal expansion coefficient in the determined volume fraction;
(d) contacting the ultrahard particles of (a) and the matrix material of (c) to form a reaction volume; and
(e) consolidating and sintering the reaction volume at a pressure and a temperature at which the ultrahard particles are crystallographically or thermodynamically stable.
2. A method according to claim 1, wherein the matrix material is selected from the group consisting of the oxides, nitrides, carbides, oxynitrides, oxycarbides and carbonitrides of aluminium, titanium, silicon, vanadium, zirconium, niobium, hafnium, tantalum, chromium, molybdenum and tungsten, and combinations thereof.
3. A method according to claim 1, wherein the matrix material is nano-grain sized and comprises chromium nitride (CrN andor Cr2N), titanium nitride (TiN), tantalum nitride (TaN andor Ta3N5), niobium nitride (NbN), vanadium nitride (VN), zirconium nitride (ZrN), hafnium nitride (HfN), titanium carbide (TiC), tantalum carbide (TaC andor Ta2C), niobium carbide (NbC), vanadium carbide (VC), zirconium carbide (ZrC), or hafnium carbide (HfC), or combinations thereof.
4. A method according to claim 1, wherein the ultrahard composite material comprises diamond andor cBN particles.
5. A method according to claim 1, wherein the composite material comprises micron or sub-micron diamond andor cBN particles.
6. A method according to claim 1, wherein the ultrahard particles are contacted with a suspension of the matrix material in order to coat the ultrahard particles, which coated particles are recovered, thereby to form the reaction volume.
7. A method according to claim 1, wherein the matrix of the composite material so produced comprises a single phase solid solution of general formula M\u2032M\u20331\u2212XN, wherein x is in the range 0.1 to 0.9, and M\u2032 and M\u2033 are any two metal elements selected from Ti, Ta, V, Nb, Zr, Cr, W and Mo.
8. A method according to claim 7, wherein the matrix of the composite material so produced comprises a single phase solid solution of general formula TixTa1\u2212xN, wherein x is in the range 0.1 to 0.9.
9. A method according to claim 7, wherein the matrix of the composite material so produced comprises a single phase solid solution of general formula TixCr1\u2212xN, wherein x is in the range 0.1 to 0.9.
10. A method according to claim 1, wherein the matrix of the composite material so produced is a chromium nitride phase having the formula Cr2N.
11. An ultrahard composite material comprising cBN andor diamond ultrahard abrasive particles dispersed in a TixTa1\u2212xN solid solution single phase matrix, where x is 0.1 to 0.9.
12. An ultrahard composite material comprising cBN andor diamond ultrahard abrasive particles dispersed in a TixCri\u2212xN solid solution single phase matrix, where x is 0.1 to 0.9.
13. An ultrahard composite material comprising cBN andor diamond ultrahard abrasive particles dispersed in a Cr2N matrix.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. A washing device for a water treatment apparatus, the washing device comprising:
circulation members connected to passages of the water treatment apparatus to circulate wash water through the passages of the water treatment apparatus;
a circulation module connected to the circulation members for circulating the wash water through the passages of the water treatment apparatus, with the circulation members thereby washing the passages of the water treatment apparatus;
a drainpipe connected to the circulation members;
a passage switching unit connected to a portion where the circulation members are coupled to the drainpipe to switch passage of the wash water; and
a circulation pump connected to the circulation members to selectively circulate the wash water in the connection pipes through the drainpipe or the passages of the water treatment apparatus.
2. The washing device of claim 1, wherein the circulation module further comprises a wash water detection unit measuring a flow of the wash water to determine whether the circulation module operates normally or not.
3. The washing device of claim 2, wherein the wash water detection unit is arranged at a wash water outlet side of the circulation pump.