1. A process for preparing potassium titanate whisker used for friction material features that titanium dioxide and potassium source are used as raw materials and K is used as K₂O-MoO₃The compound fluxing agent is taken as a cosolventThe potassium titanate whisker for the friction material is prepared by a flux method.

2. The method for preparing potassium titanate whiskers for a friction material according to claim 1, comprising the following steps:

(1) uniformly mixing titanium dioxide and a potassium source serving as raw materials, adding part of composite fluxing agent, uniformly mixing the composite fluxing agent with the raw materials, and adding the mixture into a reaction container;

(2) heating after the charging is finished, adding a part of composite fluxing agent after the heating is finished, and controlling the temperature for 10-30 min;

(3) heating again after the temperature control is finished, adding the rest composite fluxing agent after the temperature control is finished, keeping the temperature for 2-5 hours, and cooling to 800 ℃ after the temperature control is finished to obtain potassium tetratitanate whiskers;

(4) dispersing the potassium tetratitanate whisker in cold water, stirring for 1-2 h in hot water at 50-80 ℃, adding dilute sulfuric acid to neutralize potassium ions, staying for 3h at 800-1250 ℃, stirring for 1-2 h in hot water at 50-80 ℃, and drying at 350 ℃ to obtain the potassium hexatitanate whisker.

3. The method for producing potassium titanate whiskers for a friction material according to claim 1 or 2, wherein a molar ratio of a titanium element and a potassium element in the titanium dioxide and potassium source is 4.0 to 6.0: 1.

4. The method of producing potassium titanate whiskers for a friction material according to claim 1 or 2, characterized in that the potassium source is any one of potassium oxide, anhydrous potassium carbonate, anhydrous potassium bicarbonate, potassium nitrate, or potassium hydroxide.

5. The method for preparing potassium titanate whiskers for a friction material according to claim 1 or 2, characterized in that the amount of the composite fluxing agent is 0.5-3% of the mass of the potassium source; k in the composite fluxing agent₂O-MoO₃The molar ratio of (A) to (B) is 1.5-3.5: 1.

6. The method for producing potassium titanate whiskers for a friction material according to claim 2, wherein the amount of the composite flux added in step (1) is 30% by mass of the composite flux, and the amount of the composite flux added in step (2) is 40% by mass of the composite flux.

7. The method for preparing potassium titanate whiskers for a friction material according to claim 2, wherein the temperature is raised to 800-900 ℃ at a temperature rise rate of 1-5 ℃/min after the addition in the step (2) is completed; and (3) raising the temperature to 1000-1250 ℃ again at a temperature raising rate of 1-10 ℃/min.

8. The method for preparing potassium titanate whiskers for a friction material according to claim 2, wherein the temperature is raised to 900 ℃ at a temperature rise rate of 2 ℃/min after the addition in the step (2) is completed; and (3) raising the temperature to 1150 ℃ again at a temperature raising rate of 8 ℃/min.

Background

With the research and development of the potassium titanate whisker, the cost is lower and lower, and the potassium titanate whisker has very good performance and is widely applied to reinforcing materials, friction materials, heat insulation materials, insulating materials and the like. Wherein, the potassium hexatitanate whisker has the performances of high-temperature sound absorption, chemical stability, insulativity, excellent corrosion resistance and the like, and has the structural composition of K₂Ti₆O₁₃The structure is a chain tunnel type structure, K⁺The ions are arranged in the middle of the tunnel, and the structural characteristics enable the ions to be used in friction materials. The flux method is a common method for synthesizing potassium hexatitanate whiskers, but the method has the defects of easy corrosion to equipment, low yield, large range of diameter and length of the whiskers and influence on further application of the whiskers.

Disclosure of Invention

Aiming at the problems in the prior art, the invention aims to provide a preparation method of potassium titanate whiskers for a friction material.

In order to solve the problems, the technical scheme adopted by the invention is as follows:

a process for preparing potassium titanate whisker used for friction material uses titanium dioxide and potassium source as raw materials and K₂O-MoO₃The composite fluxing agent is a cosolvent, and the potassium titanate whisker for the friction material is prepared by adopting a flux method. The method specifically comprises the following steps:

(1) uniformly mixing titanium dioxide and a potassium source serving as raw materials, adding part of composite fluxing agent, uniformly mixing the composite fluxing agent with the raw materials, and adding the mixture into a reaction container;

(2) heating after the charging is finished, adding a part of composite fluxing agent after the heating is finished, and controlling the temperature for 10-30 min;

(3) heating again after the temperature control is finished, adding the rest composite fluxing agent after the temperature control is finished, keeping the temperature for 2-5 hours, and cooling to 800 ℃ after the temperature control is finished to obtain potassium tetratitanate whiskers;

(4) dispersing the potassium tetratitanate whisker in cold water, stirring for 1-2 h in hot water at 50-80 ℃, adding dilute sulfuric acid to neutralize potassium ions, staying for 3h at 800-1250 ℃, stirring for 1-2 h in hot water at 50-80 ℃, and drying at 350 ℃ to obtain the potassium hexatitanate whisker.

According to the preparation method of the potassium titanate whisker for the friction material, the molar ratio of titanium element to potassium element in titanium dioxide and a potassium source is 4.0-6.0: 1.

According to the preparation method of the potassium titanate whisker for the friction material, the potassium source is any one of potassium oxide, anhydrous potassium carbonate, anhydrous potassium bicarbonate, potassium nitrate or potassium hydroxide.

The preparation method of the potassium titanate whisker for the friction material comprises the following steps that the using amount of the composite fluxing agent is 0.5-3% of the mass of a potassium source; k in the composite fluxing agent₂O-MoO₃The molar ratio of (A) to (B) is 1.5-3.5: 1.

According to the preparation method of the potassium titanate whisker for the friction material, the amount of the composite fluxing agent added in the step (1) is 30% of the mass of the composite fluxing agent, and the amount of the composite fluxing agent added in the step (2) is 40% of the mass of the composite fluxing agent.

After the material is added in the step (2), the temperature is increased to 800-900 ℃ at a heating rate of 1-5 ℃/min; and (3) raising the temperature to 1000-1250 ℃ again at a temperature raising rate of 1-10 ℃/min.

The preparation method of the potassium titanate whisker for the friction material comprises the following steps of (1) heating to 900 ℃ at a heating rate of 2 ℃/min after the material is added in the step (2); and (3) raising the temperature to 1150 ℃ again at a temperature raising rate of 8 ℃/min.

Has the advantages that: compared with the prior art, the invention has the advantages that:

(1) the invention adopts K₂O and MoO₃The mixture is used as a composite fluxing agent to prepare the potassium titanate whisker for the friction material, and the composite fluxing agent can effectively reduce the corrosion of reaction raw materials to reaction equipment; in the reaction process, the composite fluxing agent is added in batches, so that the effect of the composite fluxing agent can be exerted to the maximum, the reaction raw materials are reacted more completely, the raw material waste is reduced, and the yield is increased.

(2) The method is matched with the adding mode of the composite fluxing agent in the preparation process, and adopts a segmented heating and segmented reaction mode for the heating mode, so that the reaction rate is increased, the yield is improved, the length and the diameter of the obtained potassium hexatitanate whisker are more uniform, and the further application of the potassium hexatitanate is facilitated.

Detailed Description

In order to make the aforementioned objects, features and advantages of the present invention comprehensible, embodiments accompanied with examples are described in detail below.

Example 1

A preparation method of potassium titanate whiskers for a friction material specifically comprises the following steps:

(1) will K₂O and MoO₃Uniformly mixing the components in a molar ratio of 1.5:1 to obtain a composite fluxing agent, and dividing the composite fluxing agent into three parts according to the mass, wherein the three parts are respectively 30%, 30% and 40% of the mass of the composite fluxing agent for later use; uniformly mixing titanium dioxide and anhydrous potassium carbonate serving as raw materials, adding 30% of composite fluxing agent, uniformly mixing with the raw materials, and adding into a reaction container; the molar ratio of titanium element to potassium element in the titanium dioxide and potassium source is 4.0: 1; the using amount of the composite fluxing agent is 3.5 percent of the mass of the potassium source;

(2) after the charging is finished, the temperature is raised to 800 ℃ at the heating rate of 1 ℃/min, and after the heating is finished, 30 percent of composite fluxing agent is added, and the temperature is controlled for 30 min;

(3) after the temperature control is finished, raising the temperature to 1000 ℃ again at the temperature raising rate of 5 ℃/min, adding the remaining 40% of the composite fluxing agent after the temperature raising is finished again, keeping the temperature for 2 hours, and cooling to 800 ℃ after the temperature control is finished to obtain potassium tetratitanate whiskers;

(4) dispersing the potassium tetratitanate whisker in cold water, stirring in hot water at 50 ℃ for 2h, adding dilute sulfuric acid to neutralize potassium ions, staying at 800 ℃ for 3h, stirring in hot water at 80 ℃ for 1h, and drying at 350 ℃ to obtain the potassium hexatitanate whisker. The potassium hexatitanate whisker has an average diameter of 0.6 to 1.5 μm, an average length of 10 to 21 μm, and a yield of 95.9%.

Example 2

A preparation method of potassium titanate whiskers for a friction material specifically comprises the following steps:

(1) will K₂O and MoO₃Uniformly mixing the components in a molar ratio of 2.0:1 to obtain a composite fluxing agent, and dividing the composite fluxing agent into three parts according to the mass, wherein the three parts are respectively 30%, 30% and 40% of the mass of the composite fluxing agent for later use; uniformly mixing titanium dioxide and potassium oxide serving as raw materials, adding 30% of composite fluxing agent into the mixture, uniformly mixing the mixture with the raw materials, and adding the mixture into a reaction container; oxidation of hydrogen dioxideThe molar ratio of the titanium element to the potassium element in the titanium and potassium sources is 6.0: 1; the using amount of the composite fluxing agent is 0.5 percent of the mass of the potassium source;

(2) after the charging is finished, the temperature is increased to 900 ℃ at the heating rate of 4 ℃/min, and after the heating is finished, 30 percent of composite fluxing agent is added, and the temperature is controlled for 10 min;

(3) after the temperature control is finished, raising the temperature to 1250 ℃ again at the temperature raising rate of 10 ℃/min, adding the remaining 40 percent of composite fluxing agent after the temperature raising is finished again, keeping the temperature for 2 hours, and cooling to 800 ℃ after the temperature control is finished to obtain potassium tetratitanate whiskers;

(4) dispersing the potassium tetratitanate whisker in cold water, stirring in hot water at 50 ℃ for 2h, adding dilute sulfuric acid to neutralize potassium ions, staying at 800 ℃ for 3h, stirring in hot water at 80 ℃ for 1h, and drying at 350 ℃ to obtain the potassium hexatitanate whisker. The potassium hexatitanate whisker has an average diameter of 1.0 to 2.3 μm, an average length of 10 to 18 μm, and a yield of 96.5%.

Example 3

A preparation method of potassium titanate whiskers for a friction material specifically comprises the following steps:

(1) will K₂O and MoO₃Uniformly mixing the components in a molar ratio of 3.0:1 to obtain a composite fluxing agent, and dividing the composite fluxing agent into three parts according to the mass, wherein the three parts are respectively 30%, 30% and 40% of the mass of the composite fluxing agent for later use; uniformly mixing titanium dioxide and potassium oxide serving as raw materials, adding 30% of composite fluxing agent into the mixture, uniformly mixing the mixture with the raw materials, and adding the mixture into a reaction container; the molar ratio of titanium element to potassium element in the titanium dioxide and potassium source is 5.0: 1; the using amount of the composite fluxing agent is 1.5 percent of the mass of the potassium source;

(2) after the charging is finished, the temperature is increased to 900 ℃ at the heating rate of 2 ℃/min, and after the heating is finished, 30 percent of composite fluxing agent is added, and the temperature is controlled for 30 min;

(3) after the temperature control is finished, raising the temperature to 1150 ℃ again at the temperature raising rate of 8 ℃/min, adding the remaining 40% of the composite fluxing agent after the temperature raising is finished again, keeping the temperature for 2 hours, and cooling to 800 ℃ after the temperature control is finished to obtain the potassium tetratitanate whisker;

(4) dispersing the potassium tetratitanate whisker in cold water, stirring in hot water at 50 ℃ for 2h, adding dilute sulfuric acid to neutralize potassium ions, staying at 800 ℃ for 3h, stirring in hot water at 80 ℃ for 1h, and drying at 350 ℃ to obtain the potassium hexatitanate whisker. The potassium hexatitanate whisker has an average diameter of 0.5 to 1.3 μm, an average length of 8 to 15 μm, and a yield of 97.6%.

Example 4

A preparation method of potassium titanate whiskers for a friction material specifically comprises the following steps:

(1) will K₂O and MoO₃Uniformly mixing the components in a molar ratio of 3.5:1 to obtain a composite fluxing agent, and dividing the composite fluxing agent into three parts according to the mass, wherein the three parts are respectively 30%, 30% and 40% of the mass of the composite fluxing agent for later use; uniformly mixing titanium dioxide and anhydrous potassium bicarbonate serving as raw materials, adding 30% of composite fluxing agent, uniformly mixing with the raw materials, and adding into a reaction container; the molar ratio of titanium element to potassium element in the titanium dioxide and potassium source is 4.0: 1; the using amount of the composite fluxing agent is 1.5 percent of the mass of the potassium source;

(2) after the charging is finished, the temperature is increased to 900 ℃ at the heating rate of 2 ℃/min, and after the heating is finished, 30 percent of composite fluxing agent is added, and the temperature is controlled for 30 min;

(3) after the temperature control is finished, raising the temperature to 1150 ℃ again at the temperature raising rate of 8 ℃/min, adding the remaining 40% of the composite fluxing agent after the temperature raising is finished again, keeping the temperature for 2 hours, and cooling to 800 ℃ after the temperature control is finished to obtain the potassium tetratitanate whisker;

(4) dispersing the potassium tetratitanate whisker in cold water, stirring in hot water at 50 ℃ for 2h, adding dilute sulfuric acid to neutralize potassium ions, staying at 800 ℃ for 3h, stirring in hot water at 80 ℃ for 1h, and drying at 350 ℃ to obtain the potassium hexatitanate whisker. The potassium hexatitanate whisker has an average diameter of 0.6 to 1.5 μm, an average length of 6 to 12 μm, and a yield of 95.3%.