Nickel-coated hexagonal boron nitride nanosheet composite powder, preparation and high performance composite ceramic cutting tool material

Patent metadata

Field	Value
Publication number	US-11319251-B2
Application number	US-201916765131-A
Country	US
Kind code	B2
Filing date	Nov 8, 2019
Priority date	Jan 29, 2019
Publication date	May 3, 2022
Grant date	May 3, 2022

Abstract

The invention relates to nickel-coated hexagonal boron nitride nanosheet composite powder, its preparation and high-performance composite ceramic cutting tool material. The composite powder has a core-shell structure with BNNS as the core and Ni as the shell. The self-lubricating ceramic cutting tool material is prepared by wet ball milling mixing and vacuum hot-pressing sintering with a phase alumina as the matrix, tungsten-titanium carbide as the reinforcing phase, nickel-coated hexagonal boron nitride nanosheet composite powder as the solid lubricant and magnesium oxide and yttrium oxide as the sintering aids. The invention also provides preparation methods of the nickel-coated hexagonal boron nitride nanosheet composite powder and the self-lubricating ceramic cutting tool material.

First claim

What is claimed is:

1. A method for preparing a nickel-coated hexagonal boron nitride nanosheet composite powder (BNNS@Ni) comprising the following steps:
(1) adding BNNS powder into isopropanol, ultrasonically dispersing for 20-30 min, and then centrifugally separatinge to obtain dispersed BNNS powder;
(2) adding the dispersed BNNS powder into a sensitizing solution, ultrasonically oscillating and stirring for 10-15 min, centrifugally separating after tin particles in a sensitizing solution are filtered out, and washing once with distilled water to obtain sensitized BNNS powder;
wherein the sensitizing solution comprises: 10-15 g/L of stannous chloride dihydrate, the balance is isopropanol, and 3-5 g/L of tin particles are added;
(3) the sensitized BNNS powder obtained in step (2) is added into an activating solution, ultrasonically oscillated and stirred for 10-20 min, centrifugally separated and washed to neutrality with distilled water to obtain activated BNNS powder; then it is added into a PVP solution, ultrasonically oscillated and stirred for 5-10 min to prepare an activated BNNS suspension, which is sealed for later use;
the components of the activating solution are: 0.2-0.5 g/L of palladium chloride (PdCl 2 ), 5-10 mL/L of concentrated hydrochloric acid, 5-10 mg/L of polyvinylpyrrolidone (PVP), and the balance is distilled water;
(4) electroless plating solution is prepared, and the components of the electroless plating solution are: 15-25 g/L of nickel sulfate hexahydrate, 50-60 g/L of ethylenediamine tetraacetic acid disodium dihydrate, 40-50 g/L of ammonium sulfate, 15-25 mL/L of a first dose of hydrazine hydrate, 5-10 mg/L of polyvinylpyrrolidone, 0.2-0.5 mg/L of potassium iodide, a pH adjuster that makes the pH value of the electroless plating solution at 10-11, and the balance is distilled water; in addition, 15-25 mL/L of a second dose of equal amount of hydrazine hydrate is prepared for later use;
the activated BNNS suspension obtained in step (3) is added into the prepared electroless plating solution; first, the plating is carried out for 5-10 min in a constant temperature water bath at 85-90° C. and under ultrasonic oscillation condition, then the second dose of hydrazine hydrate is added dropwise under stirring condition; afterwards the plating is carried out in a constant temperature water bath at 50-60° C. and under ultrasonic oscillation condition, and the pH adjuster is dripped at any time to keep the pH value of the electroless plating solution at 10-11;
(5) after the plating in step (4) is completed, the solid particles are centrifugally separated and washed to neutrality with distilled water, then washed with absolute ethanol for 2-3 times, and dried in a vacuum drying oven at 30-40° C. for 10-15 h to obtain nickel-coated hexagonal boron nitride nanosheet composite powder.

2. The method for preparing the nickel-coated hexagonal boron nitride nanosheet composite powder as claimed in claim 1 , wherein the average particle size of the tin particles in step (2) is 1-2 mm; when the BNNS powder is sensitized in step (2), BNNS powder is added by 1-2 g/L per liter of the sensitizing solution.

3. The method for preparing the nickel-coated hexagonal boron nitride nanosheet composite powder as claimed in claim 1 , wherein when the BNNS powder is activated in step (3), the addition amount of BNNS powder is added by 0.5-1 g/L per liter of the activating solution.

4. The method for preparing the nickel-coated hexagonal boron nitride nanosheet composite powder as claimed in claim 1 , wherein the concentration of the PVP solution in step (3) is 5-10 mg/L in the distilled water.

5. The method for preparing the nickel-coated hexagonal boron nitride nanosheet composite powder as claimed in claim 1 , wherein in step (4), the pH adjuster of the electroless plating solution is NaOH solution with a mass fraction of 7-8%.

6. The method for preparing the nickel-coated hexagonal boron nitride nanosheet composite powder as claimed in claim 1 , wherein in step (4), the components of the electroless plating solution are: 20 g/L of nickel sulfate hexahydrate, 55 g/L of ethylenediamine tetraacetic acid disodium dihydrate, 45 g/L of ammonium sulfate, 20 mL/L of the first dose of hydrazine hydrate, 7 mg/L of PVP, 0.3 mg/L of potassium iodide, pH adjuster to makes the pH value of the electroless plating solution 10-11, and the balance is the distilled water; wherein 20 mL/L of the second dose of equal amount of hydrazine hydrate is prepared for later use.

7. The method for preparing the nickel-coated hexagonal boron nitride nanosheet composite powder as claimed in claim 1 , wherein the preparation steps of the electroless plating solution in step (4) are as follows:
1) NiSO 4 .6H 2 O and Na 2 C 10 H 14 N 2 O 8 .2H 2 O are weighed, respectively added into the distilled water, ultrasonically oscillated and stirred for dissolution to obtain NiSO 4 .6H 2 O solution and Na 2 C 10 H 14 N 2 O 8 .2H 2 O solution, respectively;
2) under ultrasonically oscillating and stirring conditions, NiSO 4 .6H 2 O solution is added into Na 2 C 10 H 14 N 2 O 8 .2H 2 O solution to obtain solution a;
3) (NH 4 ) 2 SO 4 is added into solution a, ultrasonically oscillated and stirred for dissolution to obtain solution b;
4) NaOH is added into the distilled water, ultrasonically oscillated and stirred for dissolution to prepare NaOH solution with mass fraction of 7-8%;
5) under the conditions of ultrasonically oscillating and stirring, the NaOH solution obtained in step 4) is added dropwise to solution b until the pH value reaches 10-11 to obtain solution c;
6) the first dose of hydrazine hydrate is dripped into the solution c under the conditions of ultrasonically oscillating and stirring, and the distilled water is added to the total volume of the electroless plating solution to obtain solution d;
7) PVP and KI are added into the solution d successively, ultrasonically oscillated and stirred for dissolution to obtain the electroless plating solution.

8. The method for preparing the nickel-coated hexagonal boron nitride nanosheet composite powder as claimed in claim 1 , wherein during the electroless plating in step (4), the BNNS powder is added by 0.2-0.5 g/L per liter of the electroless plating solution.

9. A self-lubricating ceramic cutting tool material added with nickel-coated hexagonal boron nitride nanosheet composite powder, which is prepared by wet ball milling mixing and vacuum hot-pressing sintering with a phase alumina (α-Al 2 O 3 ) as the matrix, tungsten-titanium carbide ((W,Ti)C) as the reinforcing phase, magnesium oxide (MgO) and yttrium oxide (Y 2 O 3 ) as the sintering aids; wherein the nickel-coated hexagonal boron nitride nanosheet (BNNS@Ni) composite powder is used as a solid lubricant;
the mass percentage of each component is: 28-50% of α-Al 2 O 3 , 46-70% of (W,Ti)C, 0.2-3% of the nickel-coated hexagonal boron nitride nanosheet composite powder based on the mass of BNNS in the composite powder, 0.4-1% of MgO and 0.4-1% of Y 2 O 3 .

10. The self-lubricating ceramic cutting tool material added with nickel-coated hexagonal boron nitride nanosheet composite powder as claimed in claim 9 , wherein the mass percentage of each component is: 30-46% of α-Al 2 O 3 , 51-68% of (W,Ti)C, 0.2-1% of BNNS@Ni based on the mass of BNNS in the composite powder, 0.5-1% of MgO, and 0.5-1% of Y 2 O 3 ; the sum of the components is 100%;
alternatively, the self-lubricating ceramic cutting tool material added with nickel-coated hexagonal boron nitride nanosheet composite powder, wherein the mass percentage of each component is: 32.6-32.7% of α-Al 2 O 3 , 65-67% of (W,Ti)C, 0.3-0.4% of BNNS@Ni based on the mass of BNNS in the composite powder, 0.5%

Assignees

• Univ Qilu Technology

Inventors

• Xu Chonghai
• Wu Guangyong
• Xiao Guangchun
• Yi Mingdong
• Chen Zhaoqiang
• Zhang Jingjie

Classifications

• B22F1/18

  Non-metallic particles coated with metal · CPC title

• C04B2235/767

  Hexagonal symmetry, e.g. beta-Si3N4, beta-Sialon, alpha-SiC or hexa-ferrites · CPC title

• C04B2235/5436

  micrometer sized, i.e. from 1 to 100 micron · CPC title

• C04B2235/3839

  Refractory metal carbides · CPC title

• C04B2235/5292

  Flakes, platelets or plates · CPC title