CN107868950A - A kind of TiB2The method of powder surface no-palladium activating chemical plating nickel-molybdenum-phosphorus ternary alloy three-partalloy - Google Patents

Abstract

The invention belongs to the field of electroless plating, and relates to a method for palladium-free activated chemical plating of nickel-molybdenum-phosphorus ternary alloy on the surface of _TiB2 powder, which solves the problem of palladium-sensitive electroless plating of nickel-molybdenum-phosphorus ternary alloy on the surface of _TiB2 powder. traditional methods of activation. Provided is a palladium-free activation method for electroless nickel-molybdenum-phosphorus ternary alloy plating, wherein the electroless nickel-molybdenum-phosphorus ternary alloy is plated after being treated with a palladium-free pretreatment solution. The pretreatment before electroless nickel-molybdenum-phosphorus ternary alloy plating is to use the pretreatment solution to activate the surface of _TiB2 powder at a certain temperature, so that the electroless nickel-molybdenum-phosphorus ternary alloy solution directly undergoes an autocatalytic reaction to obtain Coating layer of nickel-molybdenum-phosphorus ternary alloy. The invention replaces the complex palladium activation pretreatment method with the pretreatment of the powder and the corresponding electroless nickel-molybdenum-phosphorus ternary alloy formula. The TiB ₂ powder after electroless nickel-molybdenum-phosphorus plating can improve its sintering performance and can be widely used in various fields.

Description

A method for palladium-free activated electroless nickel-molybdenum-phosphorus ternary alloy plating on the surface of TiB2 powder

technical field

The invention belongs to the field of electroless plating, in particular to a method for palladium-free activated electroless nickel-molybdenum-phosphorus ternary alloy plating on the surface of _TiB2 powder.

Background technique

In boride ceramics, TiB ₂ has become one of the hot materials for preparing metal-ceramic composites due to its high melting point (2980°C), high hardness (3370HV), and good wear resistance. It is widely used in aerospace, weapons, etc. Equipment and non-ferrous metal smelting and other fields. Relevant patents have reported about the preparation of metal Ni-coated _TiB2 powders. In foreign countries, self-propagating high-temperature synthesis technology is mainly used, and there are also patents (ZL200910220166.3 A new method of palladium-free _activated electroless nickel-phosphorus alloy plating on the surface of TiB2 powders. Method and ZL201110378215.X TiB ₂ powder direct electroless nickel-phosphorus alloy plating solution and its preparation and use) introduces the method of electroless plating to prepare TiB ₂ composite powder nickel-phosphorus binary alloy.

However, there are few reports on ternary alloys, especially nickel-molybdenum-phosphorus ternary alloy-coated TiB ₂ ceramic powders, and studies have shown that the early metal system selection is mostly a single Ni metal, but the addition of a single metal often improves performance. not ideal. It is found that when the content of Ni is too high, the deterioration of mechanical properties will occur, which is considered to be caused by the continuous structure formed by brittle Ni ₃ B. It has been found that adding some other metals, Mo, Cr, Fe, etc. at the same time as Ni is added, is beneficial to improve the densification and performance of the material. By comparing the three systems of TiB ₂ , TiB ₂ -Ni and TiB ₂ -(Ni, Mo), it is found that the addition of Mo helps to improve the density, hardness and flexural strength of the material.

Electroless plating is an advanced method for preparing metal-ceramic composite powders. There are few reports on the introduction of metal Ni and Mo through the electroless plating method. The key to electroless nickel-molybdenum-phosphorus ternary alloy plating on the surface of TiB ₂ powder is how to initiate the electroless plating process. The traditional process is to use SnCl ₂ -PdCl ₂ Sensitization-activation method, but the process is complicated, the use of PdCl ₂ is expensive, and it is easy to pollute the plating solution, so its application is limited. At present, the electroless plating on the surface of TiB ₂ powder still stays in the traditional method of using sensitization-activation The activation method does not involve the preparation process of nickel-molybdenum-phosphorus direct electroless plating coating TiB ₂ powder. The present invention can solve this problem well by using a pretreatment solution to treat the powder, so that the difficult-to-plate electroless nickel-molybdenum-phosphorus three The elemental alloy is coated on the surface of the powder.

Contents of the invention

Purpose of the invention:

The object of the present invention is to provide a kind of TiB ₂ The method for palladium-free activated electroless nickel-molybdenum-phosphorus ternary alloy plating on the surface of TiB powder. It solves the problems that the traditional process adopts the SnCl ₂ -PdCl ₂ activation-sensitization method, the process is complicated, the use of PdCl ₂ is expensive, and the plating solution is easily polluted. Realize a method for obtaining multi-element cermet composite powder by electroless plating, especially for the sintering of _TiB2- based cermet while introducing metallic nickel and molybdenum.

Electroless nickel plating is performed on TiB ₂ powder. First, the powder is pretreated by roughening, sensitization, activation, etc., and then electroless nickel plating is performed. Aiming at the activation stage, the present invention proposes a palladium-free activation process, that is, the powder is pretreated before the electroless nickel plating, and the sensitization-activation steps often used in the electroless plating of common ceramic powders are canceled.

Technical solutions:

The present invention is realized by following technical scheme:

A kind of _TiB The method for palladium-free activated electroless nickel-molybdenum-phosphorus alloy plating on the powder surface, the method may further comprise the steps:

a. Pretreatment stage: Activate TiB ₂ powder, the process is: nickel acetate 10-20 g/L, ammonium citrate 15-30 g/L, sodium hypophosphite 10-20 g/L, pH: 5- 6. The temperature is 80-90℃, and the processing time is 10-30min;

b. Electroless nickel-molybdenum-phosphorus ternary alloy treatment stage: Add the preheated electroless nickel-molybdenum-phosphorus ternary alloy plating solution to the pretreated TiB ₂ powder to perform ternary nickel-molybdenum-phosphorus alloy plating Coating; electroless nickel plating molybdenum phosphorus ternary alloy bath composition and content are as follows: nickel chloride 10-15g/L, sodium molybdate 0.6-1.2g/L, sodium hypophosphite 10-15g/L, sodium citrate 35 -50g/L, borax 1-3g/L, Tween-80: 0.01-0.05g/L, thiourea 0.5-1.5mg/L, pH regulator to make the solution pH in the range of 8-10, solvent is deionized Water; the plating process is carried out in a constant temperature water bath, the temperature is kept at 88-92 ° C, and the treatment time is 40-60 minutes;

c. Drying stage: After the plating is completed, the plating solution is washed several times, and after settling, it is dried at a constant temperature at 60°C to obtain TiB ₂ powder coated with nickel-plated molybdenum-phosphorus ternary alloy.

The raw material TiB ₂ powder in the pretreatment stage is 3-5 micron self-propagating high-temperature synthesized TiB ₂ powder.

The pH regulator in the electroless nickel-molybdenum-phosphorus ternary alloy treatment stage selects ammonia water with a volume ratio of 20%, borax at 1-3g/L and Tween-80 at 0.01-0.05g/L.

Using SEM (scanning electron microscope) and EDS energy spectrum analysis to analyze the surface morphology and composition of the powder before and after plating, the results show that the Ni-Mo-P alloy can be successfully deposited on the TiB ₂ particles, and the energy spectrum analysis results It shows that the coating contains Ni, Mo, P, Ti elements, the content of nickel is the highest, and the coating contains Mo.

Advantages and effects:

Metal-coated ceramic composite powder refers to coating a layer of heterogeneous metal on the surface of ceramic particles to form a composite ceramic powder, which has both a metal coating and a ceramic core. This new technology can control the agglomeration state of the powder and improve its dispersion characteristics; realize particle surface modification, improve the uniform dispersion of the constituent phase and sintering additives, and improve the performance of the sintering process; improve the heterogeneous combination state in composite ceramics and reduce the interface the residual stress. The research on metal-coated ceramic powder has become a hotspot in the preparation of cermets. A lot of research has been done on the preparation process of TiB ₂ cermet composite powder at home and abroad. The preparation methods of metal Ni-coated _TiB2 ceramic powder are usually as follows: mechanical mixing, high-energy ball milling, self-propagating high-temperature synthesis, in-situ reaction, sol-gel, electroless plating, etc. Regarding the preparation of metal Ni-coated TiB ₂ powder, the self-propagating high-temperature synthesis technology is mainly used abroad, and there are few introductions to the preparation of TiB ₂ composite powder by electroless plating.

The inventor of this patent, through a large number of experiments, based on the principle of electroless plating, invented the patent of realizing palladium-free activation by heat treatment of powder, and realized a kind of palladium-free electroless nickel-phosphorous binary alloy plating. In order to simplify the process, the inventor was in In 2009 and 2011, two invention patents were applied (ZL200910220166.3 A new method for palladium-free activated electroless nickel-phosphorus alloy plating on the surface of TiB ₂ powder and ZL201110378215.X TiB ₂ powder direct electroless nickel-phosphorus alloy plating solution and its preparation ,Instructions). The above invention solves the problem of introducing metal nickel into the electroless plating method, but studies have shown that the addition of a single metal is often unsatisfactory for performance improvement. It is found that when the content of Ni is too high, the deterioration of mechanical properties will occur, which is considered to be caused by the continuous structure formed by brittle Ni ₃ B. It has been found that adding some other metals, Mo, Cr, Fe, etc. at the same time as Ni is added, is beneficial to improve the densification and performance of the material. By comparing the three systems of TiB ₂ , TiB ₂ -Ni and TiB ₂ -(Ni, Mo), it is found that the addition of Mo helps to improve the density, hardness and flexural strength of the material. Using conventional ternary nickel-molybdenum-phosphorus electroless plating solution, since the surface of _TiB2 has no catalytic activity, it is impossible to directly obtain the electroless plating of ternary nickel-molybdenum-phosphorus alloy on the surface of _TiB2 , and only the traditional sensitization-palladium activation method can be used. The key to electroless nickel-molybdenum-phosphorus ternary alloy plating on the surface of TiB ₂ powder is how to initiate the electroless plating process. The traditional process uses the SnCl ₂ -PdCl ₂ sensitization-activation method, and the process is complicated, and the price of PdCl ₂ is used. Expensive and easy to pollute the plating solution, so its application is limited. At present, the electroless plating on the surface of TiB ₂ powder still stays in the traditional activation method of sensitization-activation, and does not involve direct electroless plating of nickel, molybdenum, and phosphorus to coat TiB ₂ powder. The preparation process of the present invention can well solve this problem by using a pretreatment solution to treat the powder, so that the difficult-to-plate electroless nickel-molybdenum-phosphorus ternary alloy is coated on the surface of the powder. Compared with the previous literature and patents (ZL200910220166.3 A new method for palladium-free activated electroless nickel-phosphorus alloy plating on the surface of TiB ₂ powder and ZL201110378215.X TiB ₂ powder direct electroless nickel-phosphorus alloy plating solution and its preparation and use method) In terms of TiB ₂ electroless nickel-phosphorus alloy plating method and plating solution, the pretreatment activation solution process of the present invention not only has simple plating solution components and is easy to operate, but more importantly, it will not cause subsequent electroless nickel-molybdenum-phosphorus ternary plating. The plating solution of the alloy was decomposed, and the ternary alloy coating was successfully realized. If the previously invented method and the binary nickel-phosphorus plating solution were used, and then the ternary electroless plating was performed, the ternary nickel-molybdenum-phosphorus electroless plating solution showed obvious decomposition. After being treated with the pretreatment activating solution of the present invention, the ternary alloy plating solution does not decompose, the coating effect is good, and a remarkable effect has been achieved, which is the advantage of the present invention. Simultaneously, the ternary nickel-molybdenum-phosphorus plating solution of the present invention is also significantly different from the electroless nickel-molybdenum-phosphorus plating solution of the block body introduced by previous documents on the composition of the plating solution. The nickel-molybdenum-phosphorus plating solution is due to containing sodium molybdate, Generally, the deposition rate of the coating is low. The addition of borax to this plating solution can significantly increase the deposition rate, which is rarely reported in the literature. The use of Tween-80 not only makes the powder disperse more uniformly, but also increases the stability and coating of the plating solution. Cover more evenly. These are the effects that the conventional electroless nickel-molybdenum-phosphorus plating can't achieve, which is another advantage of the present invention.

The advantage of the present invention is that it realizes a method for obtaining multi-element cermet composite powder by electroless plating, especially for the sintering of _TiB2- based cermet while introducing metallic nickel and molybdenum.

Description of drawings:

Fig.1 SEM image of TiB ₂ powder before coating;

After Fig. 2 pretreatment 20min TiB ₂ The SEM topography figure of powder;

After Fig. 3 pretreatment 20min TiB ₂ The EDS energy spectrogram of powder;

Figure 4 SEM morphology of TiB ₂ powder after electroless nickel-molybdenum-phosphorus ternary alloy plating for 40 min after pretreatment;

Fig. 5 EDS spectrum of TiB ₂ powder after electroless nickel-molybdenum-phosphorus ternary alloy plating for 40 min after pretreatment.

Detailed ways:

A kind of _TiB The method for palladium-free activated electroless nickel-molybdenum-phosphorus alloy plating on the powder surface, the method may further comprise the steps:

a. Pretreatment stage: Activate TiB ₂ powder, the process is: nickel acetate 10-20 g/L, ammonium citrate 15-30 g/L, sodium hypophosphite 10-20 g/L, pH: 5- 6. The temperature is 80-90℃, and the processing time is 10-30min;

b. Electroless nickel-molybdenum-phosphorus ternary alloy treatment stage: Add the electroless nickel-molybdenum-phosphorus ternary alloy plating solution that has been preheated (the preheated temperature is the temperature at which the plating solution will be plated in the future, that is, 88-92°C) Into the pretreated _TiB2 powder, carry out the cladding of ternary nickel-molybdenum-phosphorus alloy; the composition and content of electroless nickel-molybdenum-phosphorus ternary alloy plating solution are as follows: nickel chloride 10-15g/L, sodium molybdate 0.6-1.2g/L, sodium hypophosphite 10-15g/L, sodium citrate 35-50g/L, borax 1-3g/L, Tween-80: 0.01-0.05g/L, thiourea 0.5-1.5mg /L, pH adjuster to keep the pH of the solution in the range of 8-10, the solvent is deionized water; the plating process is carried out in a constant temperature water bath, the temperature is kept at 88-92°C, and the treatment time is 40-60min;

c. Drying stage: After the plating is completed, the plating solution is washed several times, and after settling, it is dried at a constant temperature at 60°C to obtain TiB ₂ powder coated with nickel-plated molybdenum-phosphorus ternary alloy.

The raw material TiB ₂ powder in the pretreatment stage is 3-5 micron self-propagating high-temperature synthesized TiB ₂ powder.

The pH regulator in the electroless nickel-molybdenum-phosphorus ternary alloy treatment stage selects ammonia water with a volume ratio of 20%, borax at 1-3g/L and Tween-80 at 0.01-0.05g/L.

Using SEM (scanning electron microscope) and EDS energy spectrum analysis to analyze the surface morphology and composition of the powder before and after plating, the results show that the Ni-Mo-P alloy can be successfully deposited on the TiB ₂ particles, and the energy spectrum analysis results It shows that the coating contains Ni, Mo, P, Ti elements, the content of nickel is the highest, and the coating contains Mo.

Example 1

According to the aforementioned steps, the present invention takes 0.05 g of self-propagating high-temperature synthesized TiB ₂ powder of 3-5 microns and puts it into 50 mL of preheated pretreatment solution, treats it for 20 minutes, cools it rapidly, and puts the pretreatment The solution is separated from the powder. Add 50 mL of the preheated nickel-molybdenum-phosphorus ternary alloy plating solution into it.

The bath composition and process conditions of the pretreatment solution are as follows: nickel acetate 10 g/L, ammonium citrate 15 g/L, sodium hypophosphite 10 g/L, pH: 5, temperature 80°C, treatment time 10 min.

The composition and process conditions of electroless nickel-molybdenum-phosphorus ternary alloy plating solution are: nickel chloride 10g/L, sodium molybdate 0.6g/L, sodium hypophosphite 10g/L, sodium citrate 35g/L, borax 1g/L , Tween-80: 0.01g/L, thiourea 0.5mg/L, pH: 8, pH regulator 20% ammonia water, solvent is deionized water. The plating process was carried out in a constant temperature water bath, the temperature was maintained at 88°C, and the treatment time was 60 minutes.

Example 2

According to the aforementioned steps, the present invention takes 0.05 g of self-propagating high-temperature synthesized TiB ₂ powder of 3-5 microns and puts it into 50 mL of preheated pretreatment solution, treats it for 20 minutes, cools it rapidly, and puts the pretreatment The solution is separated from the powder. Add 50 mL of the preheated nickel-molybdenum-phosphorus ternary alloy plating solution into it.

The bath composition and process conditions of the pretreatment solution are as follows: nickel acetate 15 g/L, ammonium citrate 30 g/L, sodium hypophosphite 20 g/L, pH: 5, temperature 90°C, treatment time 30 minutes.

The composition and process conditions of electroless nickel-molybdenum-phosphorus ternary alloy plating solution are: nickel chloride 15g/L, sodium molybdate 1.2g/L, sodium hypophosphite 15g/L, sodium citrate 50g/L, borax 3g/L , Tween-80: 0.05g/L, thiourea 0.5mg/L, pH: 10, pH regulator 20% ammonia water, solvent is deionized water. The plating process was carried out in a constant temperature water bath, the temperature was maintained at 92°C, and the treatment time was 40min.

Example 3

As shown in Fig. 1, Fig. 1 is a SEM topography diagram of TiB ₂ powder before treatment.

As shown in Figure 2, Figure 3, Figure 4 and Figure ₅ , according to the aforementioned steps, the present invention takes 0.05 g of self-propagating high-temperature synthesized TiB powder of 3-5 microns and puts it into 50 mL of preheated pretreatment solution , treated for 20 minutes, cooled rapidly, and after settling, the pretreatment solution was separated from the powder. Add 50 mL of the preheated nickel-molybdenum-phosphorus ternary alloy plating solution into it.

The bath composition and process conditions of the pretreatment solution are as follows: nickel acetate 12.5 g/L, ammonium citrate 20 g/L, sodium hypophosphite 15 g/L, pH: 5.5, temperature 85°C, treatment time 20 minutes.

The composition and process conditions of electroless nickel-molybdenum-phosphorus ternary alloy plating solution are: nickel chloride 12.5g/L, sodium molybdate 0.8g/L, sodium hypophosphite 15g/L, sodium citrate 40g/L, borax 1.5g /L, Tween-80: 0.03g/L, thiourea 1mg/L, pH: 9, pH regulator 20% ammonia water, solvent is deionized water. The plating process is carried out in a constant temperature water bath, the temperature is maintained at 90°C, and the treatment time is 40min.

Example 4

According to the aforementioned steps, the present invention takes 0.05 g of self-propagating high-temperature synthesized TiB ₂ powder of 3-5 microns and puts it into 50 mL of preheated pretreatment solution, treats it for 20 minutes, cools it rapidly, and puts the pretreatment The solution is separated from the powder. Add 50 mL of the preheated nickel-molybdenum-phosphorus ternary alloy plating solution into it.

The bath composition and process conditions of the pretreatment solution are as follows: nickel acetate 15 g/L, ammonium citrate 20 g/L, sodium hypophosphite 15 g/L, pH: 5.5, temperature 90°C, treatment time 20 minutes.

The composition and process conditions of electroless nickel-molybdenum-phosphorus ternary alloy plating solution are: nickel chloride 15g/L, sodium molybdate 1.0g/L, sodium hypophosphite 20g/L, sodium citrate 40g/L, borax 2g/L , Tween-80: 0.02g/L, thiourea 1.5mg/L, pH: 9, pH regulator 20% ammonia water, solvent is deionized water. The plating process was carried out in a constant temperature water bath, the temperature was maintained at 99°C, and the treatment time was 50min.

Claims (3)

1. A kind of 1. TiB₂The method of powder surface no-palladium activating chemical nickel plating molybdenum phosphorus alloy, it is characterised in that this method includes following Step：

   A, pretreatment stage：To TiB₂Powder carries out activation process, and technique is：Nickel acetate 10-20 g/L, ammonium citrate 15-30 G/L, sodium hypophosphite 10-20 g/L, pH：5-6,80-90 DEG C of temperature, processing time 10-30min；

   B, chemical plating nickel-molybdenum-phosphorus ternary alloy three-partalloy processing stage：The chemical plating nickel-molybdenum-phosphorus ternary alloy plating solution having had been warmed up is added To by pretreated TiB₂In powder, the cladding of nickel ternary molybdenum phosphorus alloy is carried out；Chemical plating nickel-molybdenum-phosphorus ternary alloy plating solution Composition and content are as follows：Nickel chloride 10-15g/L, sodium molybdate 0.6-1.2g/L, sodium hypophosphite 10-15g/L, sodium citrate 35- 50g/L, borax 1-3g/L, Tween-80:0.01-0.05g/L, thiocarbamide 0.5-1.5mg/L, pH adjusting agent make pH value of solution in 8-10 In the range of, solvent is deionized water；Plating process is carried out in thermostat water bath, and temperature is maintained at 88-92 DEG C, processing time 40-60min；

   C, baking stage：After completing plating, plating solution is repeatedly washed, after sedimentation, constant temperature drying obtains plating nickel-molybdenum-phosphorus at 60 DEG C The TiB of ternary alloy three-partalloy cladding₂Powder.
2. A kind of 2. TiB according to claim 1₂The method of powder surface no-palladium activating chemical nickel plating, it is characterised in that：In advance The raw material TiB of processing stage₂TiB of the powder from the SHS process of 3-5 microns₂Powder.
3. A kind of 3. TiB according to claim 1₂The method of powder surface no-palladium activating chemical nickel plating, it is characterised in that：Change The pH adjusting agent for learning plating nickel-molybdenum-phosphorus ternary alloy three-partalloy processing stage selects the ammoniacal liquor of volume ratio 20%, 1-3g/L boraxs and 0.01- 0.05g/L Tween-80.