Preparation and application background and overview of indium fluoroborate
Indium is a silver-white, ductile metal that has good surface wear resistance. Indium fluoroborate is a compound of indium, which can be used for surface treatments such as electroplating, reagents, etc.
Preparation and application of indium fluoroborate
The preparation method of indium fluoroborate solution adopts diaphragm electrolysis method to prepare indium fluoroborate aqueous solution, which includes the following steps:
1) Use an anion exchange membrane to separate the electrolytic cell into two polar chambers, anode and anode; take 1Kg of metal indium with a mass content of 99.99% and cast it into an anode plate with a length of 0.15m and a width of 0.10m, and place it in the anode chamber. Add 1L of fluoboric acid solution with a mass concentration of 30% (meaning that 30g of fluoboric acid accounts for 100g of fluoboric acid solution) as the electrolyte; take a copper plate with a length of 0.15m and a width of 0.10m as a cathode plate and place it in the cathode chamber. A fluoroboric acid solution with a mass concentration of 30% (meaning that 30g of fluoroboric acid accounts for 30g of 100g of fluoroboric acid solution) is used as the electrolyte;
The anion exchange membrane is a homogeneous anion exchange membrane with a moisture content of 60% (mass), an exchange capacity ≥ 1.6 mol/KG (dry), and a membrane surface resistance ≤ 4.0Ω.cm2, migration number ≥ 0.97;
2) The anode and cathode are connected to the DC power supply for electrolysis. The electrolysis temperature is 35°C. After 24 hours of electrolysis with 2V DC, the indium ion content in the anode chamber reaches 205g/L. The electrolysis is stopped and fluorine is obtained in the anode chamber. Indium borate solution. The resulting product is colorless and transparent.
The electrode reaction is as follows:
Preparation and application of indium fluoroborate
Bearing bushes, as the contact part between bearings and shafts, play a decisive role in the fields of engines, compressors, internal combustion engines, etc. The traditional bearing bush is structurally composed of a base body and a friction-reducing layer located on the base body. The base body is composed of a steel back layer and a copper alloy base layer located on the steel back layer. The anti-friction layer generally uses lead-tin. Copper ternary alloy coating. However, the chemical composition of the lead-tin-copper ternary alloy layer determines that the bearing bearing capacity is limited (about 50Mpa), and it is prone to cracks, delamination and other defects. As a result, bearing manufacturers have to bear a high burden of three-guarantee claims for a long time, and at the same time limit the Improvement of OEM machine performance.
CN201110396098.3 provides a method for preparing a bearing bush with high load-bearing capacity, including the following steps:
(1) Plate a lead-tin-copper ternary alloy friction reducing layer on the substrate;
(2) Electroplating an indium layer on the lead-tin-copper ternary alloy friction reducing layer;
(3) After electroplating the indium layer, diffuse it in oil or glycerin solution for three hours at a temperature of 150°C, so that the indium layer can evenly diffuse into the lead-tin-copper ternary alloy anti-friction layer.
In step (1), the plating solution configuration is: lead fluoroborate 90-120 g/L, stannous fluoroborate 10-18 g/L, copper fluoroborate 2-3 g/L, fluoroboric acid: 70 ~80g/L, gelatin: 5~10g/L, boric acid: 20~30g/L, resorcinol: 5~10g/L, current density 1.5~2.5A/dm2, temperature: 15~20°C; lead-tin alloy is used as the anode, the content ratio of lead and tin in the lead-tin alloy is 9 nitropyridine:1; the cathode movement is 30 times/min; and deionized water is used Prepare the plating solution and use a filter pump to continuously filter the plating solution during the reaction process.
In step (2), the plating solution configuration is: indium fluoroborate 90-120 g/L, boric acid 20-30 g/L, ammonium fluoroborate: 40-50 g/L, pH value: 1.5-2.0 , Current density: 1~2 A/dm2, use deionized water to prepare the plating solution.
