CN-121992462-A - Application of HEDP cadmium plating improved process to connector

Abstract

The invention belongs to the technical field of metal surface treatment, and particularly relates to application of an HEDP cadmium plating improved process to a connector. In order to meet the requirements of the cyanide-free cadmium plating process and cyanide limitation of the aviation avionics connector, the cyanide-free cadmium plating bath solution provided by the invention mainly comprises cadmium oxide, HEDP, KOH, a softener and a brightening agent, wherein the softener comprises triethanolamine, citric acid and octyl phenol polyoxyethylene ether, and the brightening agent comprises nickel sulfate and turkish butter. The method can improve the plating speed, thoroughly abandon highly toxic cyanide, and has core indexes such as uniform plating capacity and deep plating capacity of the plating solution which are comparable with those of cyanide cadmium plating.

Inventors

• Huan Yanchang
• YU SIYUAN
• WEI JIAO
• ZHAO YANG
• LIU TING
• LIU JIAOYANG
• ZHU YANAN
• LI WEI
• CHEN YUCONG
• SHI XIAOTONG

Assignees

• 沈阳瑞特热表动力科技有限公司

Dates

Publication Date

20260508

Application Date

20260204

Claims (6)

1. 1. The application of the HEDP cadmium plating improvement process on the connector is characterized by comprising the following main components of cadmium oxide, hydroxyethylidene diphosphate, conductive salt, softener and brightening agent; The conductive salt comprises KOH, the softening agent comprises triethanolamine, citric acid and octyl phenol polyoxyethylene ether, and the brightening agent comprises nickel sulfate and turkish butter.
2. 2. The application of the HEDP cadmium plating improvement process on a connector according to claim 1, wherein the cadmium plating bath solution comprises 20-40 g/L of cadmium oxide, 110-130 ml/L of hydroxyethylidene diphosphate, 40-80 g/L of conductive salt, 10-20 ml/L of softener and 1-5 ml/L of brightening agent.
3. 3. The application of the HEDP cadmium plating improvement process on a connector according to claim 1, wherein the mass ratio of triethanolamine, citric acid and octyl phenol polyoxyethylene ether in the softening agent is (10-35): (1-3): (0.2-0.6).
4. 4. The use of an HEDP cadmium plating improvement process according to claim 1 on a connector, wherein the mass ratio of nickel sulfate to turkish butter in the brightening agent is (0.5-2): (5-15).
5. 5. The use of an HEDP cadmium plating improvement process according to claim 2 in a connector, wherein the cadmium oxide in the cadmium plating bath is 30g/L to 40g/L.
6. 6. The use of an HEDP cadmium plating improvement process according to claim 1, characterized in that the cadmium plating bath solution has a pH of 11.5-12.5, a current density of 1A/dm 2 -3A/dm 2 , a temperature of 20-40 ℃, and a cadmium plating speed of 0.45-0.6 μm/min.

Description

Application of HEDP cadmium plating improved process to connector Technical Field The invention belongs to the technical field of metal surface treatment, and particularly relates to application of an HEDP cadmium plating improved process to a connector. Background In the field of aviation and aerospace, the electric connector is a core component for realizing electric connection, signal transmission and electric power distribution in an aerospace system, and is widely applied to an avionics system, a power system and a control system of equipment such as an airplane, a rocket, a satellite, a missile and the like. The connector housing materials are aluminum alloys 6061, 7075, titanium alloy TC4, stainless steel 316L. The aluminum alloy shell cadmium plating is widely applied to the field of aviation and aerospace, and has excellent corrosion resistance in marine environments. At present, a connector shell in the aviation field mainly adopts a cadmium cyanide plating process, sodium cyanide is a main complexing agent in the cadmium cyanide plating process, and the severe toxicity of the sodium cyanide is extremely harmful to human bodies and the environment, and the wastewater treatment and the waste liquid disposal need to be strictly controlled, so that the cost is high. In recent years, environmental protection requirements are becoming stricter, and substitution of the cyanidation process is a necessary subject faced by military enterprises. At present, the core advantages of the cyanide cadmium plating system are concentrated on that ① plating layers are fine in crystallization, uniform in gloss and low in porosity, ② cyanide and cadmium ions form stable complexes, the depth capability and the covering capability are excellent, the electroplating requirement of workpieces with complex shapes is met, no obvious thickening phenomenon is caused at the edges, the ③ current density range is wide by 0.5A/dm 2-5A/dm2, the cyanide cadmium plating system is suitable for mass production of parts with different sizes and different shapes, and the ④ impurity interference resistance is strong. The existing ammonia-carboxyl complex cadmium plating, acid cadmium plating, HEDP cadmium plating and the like of the cyanide-free cadmium plating process have the advantages of poor stability and easy decomposition of the ammonia-carboxyl complex cadmium plating process, fast plating speed and poor depth capability of the acid cadmium plating process, and the HEDP cadmium plating is suitable for complex parts, good in depth capability and slow in plating speed. In order to meet the requirements of the technology of cyanide-free cadmium plating of aviation and aerospace electric connectors and the limit of cyanide, the invention is experimentally researched. Disclosure of Invention Aiming at the problems, the invention provides an application of an HEDP cadmium plating improved process to a connector. The main process comprises chemical degreasing, hot water washing, cold water washing, light-emitting, cold water washing, zinc dipping, cold water washing, zinc removing, water washing, secondary zinc dipping, water washing, nickel plating, water washing, non-cyanide cadmium plating, light-emitting, passivation and drying. The main components and contents of the cyanide-free cadmium plating bath solution are 20g/L to 40g/L of cadmium oxide, preferably 30g/L to 40g/L, 110ml/L to 130ml/L of hydroxyethylidene diphosphate (HEDP), 40g/L to 80g/L of conductive salt KOH, 10ml/L to 20ml/L of softener A and 1ml/L to 5ml/L of brightening agent B; the softening agent A comprises triethanolamine, citric acid and octyl phenol polyoxyethylene ether (OP-10), wherein the mass ratio of the triethanolamine to the citric acid to the octyl phenol polyoxyethylene ether is (10-35) to (1-3) to (0.2-0.6); The brightening agent B comprises nickel sulfate and turkish butter with the mass ratio of (0.5-2) to (5-15), wherein the turkish butter mainly comprises lactic acid ester (milk triglyceride) which is a mixture of various fatty acid glycerides. The pH of the bath solution is 11.5-12.5, the current density of cyanide-free cadmium plating is 1A/dm 2-3A/dm2, the temperature is 20-40 ℃, the cadmium plating speed is 0.45-0.6 mu m/min, the cadmium plating time is 30-90 min, and the thickness of the plating layer is 18-35 mu m. The conventional HEDP cadmium plating process is shown in the following table 1, and the HEDP (hydroxyethylidene diphosphate) and Cd 2+ are combined to form a stable five-membered ring chelate, so that the cathode polarization degree can be remarkably improved, the reduction speed of cadmium ions on the cathode surface can be reduced, the current is prevented from being concentrated on the raised parts, the current is uniformly distributed in low-current density areas such as corners, blind holes and deep cavities of a workpiece, the stability of a bath solution and the uniformity of a plating layer are ensured, however, the plating