CN108085663B

CN108085663B - Treatment method for improving corrosion resistance of AL-SiC substrate

Info

Publication number: CN108085663B
Application number: CN201711256976.5A
Authority: CN
Inventors: 张银生; 马晓娜; 刘锋; 岳纪锋; 马原
Original assignee: Shaanxi Aero Electric Co Ltd
Current assignee: Shaanxi Aero Electric Co Ltd
Priority date: 2017-12-04
Filing date: 2017-12-04
Publication date: 2020-07-03
Anticipated expiration: 2037-12-04
Also published as: CN108085663A

Abstract

The invention provides a method for increasing AL-SiThe treatment method of the anticorrosion capability of the C substrate comprises the steps of carrying out shot blasting hole sealing treatment on the surface of the AL-SiC substrate, carrying out organic solvent oil removal, acid activation and secondary zinc dipping treatment on the AL-SiC substrate, and finally carrying out chemical plating on the AL-SiC substrate for 60-90 min and then carrying out chemical plating on the AL-SiC substrate for 30-50 min. The invention adds shot blasting treatment, can reduce the casting defects of the Al-SiC substrate, improves the quality of the electroplated coating, and improves the appearance uniformity of the coating from the fact that a large number of tadpole-shaped airflow marks exist on the surface of the electroplated coating. After the processes of shot blasting treatment, chemical high phosphorus nickel plating and chemical low phosphorus nickel plating are added, the transverse corrosion of the substrate after the salt spray test is changed into the longitudinal corrosion of a point, the risk that a large number of electronic components fall off when the substrate is corroded in the use process can be avoided, the use safety level of the substrate is improved, and the corrosion-resistant protection level R_PAnd 8 stages from 5 stages. And (4) detecting the binding force of the substrate coating according to the ASTMB571 standard after salt spraying, wherein the binding force is qualified.

Description

Treatment method for improving corrosion resistance of AL-SiC substrate

Technical Field

The invention relates to the technical field of surface treatment of metal composite materials, in particular to a treatment method for improving the anticorrosion capacity of an AL-SiC substrate.

Background

The AL-SiC composite material is formed by compounding metal inorganic materials, has the characteristics of high strength, low density, good heat conductivity and the like, and can be applied to protective armor, heat-conducting radiating fins, electronic packaging substrates and the like. At present, the forming process mainly adopted in the domestic Al-SiC composite material is to infiltrate molten aluminum into preformed SiC with a porous structure through a vacuum pressure container, so that the forming speed is high, the efficiency is high, and the casting defects such as shrinkage cavities and the like are easily generated on the surface. When an Al — SiC composite material is used as an electric component substrate, it is necessary to perform surface treatment for the purpose of improving corrosion resistance of the surface of the substrate material and solderability of the surface with an electronic component.

The surface treatment process commonly used at present comprises two conventional processes of phosphorus nickel in chemical plating, thick copper plating and the like. And screening is carried out before electroplating, a substrate meeting the electroplating requirement is selected (no shrinkage cavity on the surface is visually checked), the screened qualified substrate meeting the requirement is low in proportion, less than 15%, and a small amount of shrinkage cavities are generally allowed for reducing the cost.

By adopting a phosphorus-nickel process in chemical plating, a plating layer with good thickness consistency can be obtained on the surface of the material, and the plating layer has good corrosion resistance when the thickness reaches 15-20 mu m. However, in practical operation, the applicant found that for the surface of the AL-SiC composite material with the shrinkage pores on the surface, hydrogen gas is easy to collect in the pore region during the electroless nickel plating treatment to block the exchange and circulation of the electroplating liquid, so that tadpole-shaped hydrogen gas flow is generated, and the thin coating layer in the pore region cannot effectively provide corrosion resistance. After a salt spray test of a neutral salt spray test for 96 hours is finished according to GB6458, corrosion develops from a hole area, so that a substrate has overall corrosion and a coating is integrally peeled off, and an electronic product fails. After the substrate is welded by a reflow soldering process, holes exist between the substrate and the welding surface of the component by X-ray detection, and the welding wettability is poor.

Another common treatment process is to electroplate thick copper and then mechanically process the thick copper to a designed size, so as to fill the cast shrinkage cavity with the electroplated thick copper. The copper electroplating process has the characteristic that the current density of different areas of the substrate is thick at the edge and thin in the middle, so that the consistency of the processing size cannot be effectively ensured, and subsequent mechanical treatment is required. The Al-SiC thick copper electroplating process has high processing difficulty, long treatment process flow and easy occurrence of poor coating binding force, and the electroplating time needs 6 to 8 hours to reach the required size. Due to uneven thickness distribution of the electroplated layer, the subsequent control of the size needs to be controlled by means of mechanical processing. The method has long production period and high cost.

Disclosure of Invention

In order to solve the problem that the surface treatment anticorrosion capability of the AL-SiC electronic packaging substrate formed by vacuum pressure infiltration is poor under the condition that shrinkage cavities exist on the surface of the AL-SiC electronic packaging substrate, the invention provides a treatment method for improving the anticorrosion capability of the AL-SiC substrate, solves the problems that the AL-SiC material after surface treatment is poor in anticorrosion capability and low in one-time qualification rate, and improves the welding capability of an electronic component and the substrate.

The main idea of the invention is to improve the surface corrosion resistance of the material and the first-time qualification rate of the product on the premise of ensuring the welding performance of the material by shot blasting physical hole sealing, chemical plating of high phosphorus nickel and chemical plating of low phosphorus nickel.

The technical scheme of the invention is as follows:

the treatment method for improving the corrosion resistance of the AL-SiC substrate is characterized by comprising the following steps of: the method comprises the following steps:

step 1: carrying out shot blasting hole sealing treatment on the surface of the AL-SiC substrate;

step 2: carrying out organic solvent oil removal, acid activation and secondary zinc dipping on the AL-SiC substrate subjected to the shot blasting hole sealing treatment;

and step 3: and (3) chemically plating the Al-SiC substrate treated in the step (2) with high phosphorus and nickel for 60-90 min, and then chemically plating the low phosphorus and nickel for 30-50 min.

In a further preferred aspect, the treatment method for improving the corrosion resistance of the AL-SiC substrate is characterized in that: the process parameters for carrying out shot blasting and hole sealing treatment on the surface of the AL-SiC substrate in the step 1 are as follows: adopting a pneumatic shot blasting machine, wherein the diameter of the glass shot is as follows: 0.0331-0.0234 inches (840.74-594.36 microns), shot blasting spacing of 150-250 mm, shot blasting intensity: 0.004-0.008N and 100% coverage rate.

In a further preferred aspect, the treatment method for improving the corrosion resistance of the AL-SiC substrate is characterized in that: the process parameters of the chemical plating of the high phosphorus nickel in the step 3 are as follows: solution ratio NPLF8422A:65ml/L, NPLF 8422B: 180ml/L, pH: 4.6-5.2, temperature: 85-92 ℃, time: 60min to 90 min; the technological parameters of the chemical plating of the low-phosphorus nickel are as follows: solution ratio DEUTEQ ENFINIX 666A: 60ml/L, DEUTEQ ENFINIX 666B: 150ml/L, pH: 5-7, temperature: 40-80 ℃, time: 30 min-50 min.

Advantageous effects

The Al-SiC substrate can achieve the following effects by adopting a process method:

1. the shot blasting treatment is added after casting, so that the casting defects of the Al-SiC substrate can be reduced, the qualification rate of the substrate meeting the electroplating requirement is improved from 15% to 83%, the quality of the electroplated coating is improved, and the appearance of the electroplated coating is uniform and consistent from the fact that a large number of tadpole-shaped airflow marks exist on the surface of the electroplated coating. The casting cost is reduced, and the appearance qualification rate of the electroplating coating is improved.

2. After the processes of shot blasting treatment, chemical high phosphorus nickel plating and chemical low phosphorus nickel plating are added, the transverse corrosion of the substrate after the salt spray test is changed into the longitudinal corrosion of a point, the risk that a large number of electronic components fall off when the substrate is corroded in the use process can be avoided, the use safety level of the substrate is improved, and the corrosion-resistant protection level R_PAnd 8 stages from 5 stages. And (4) detecting the binding force of the substrate coating according to the ASTMB571 standard after salt spraying, wherein the binding force is qualified.

3. The welding surface of the substrate and the component is detected by X-ray, and the welding surface is improved from a hollow state to a non-hollow state, so that the weldability of the substrate and the component is improved.

Additional aspects and advantages of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention.

Detailed Description

The following detailed description of embodiments of the invention is intended to be illustrative, and not to be construed as limiting the invention.

The specific implementation process of the surface treatment of the AL-SiC material in the embodiment mainly comprises the following steps: shot blasting hole sealing treatment → organic solvent degreasing → acid activation → secondary zinc dipping → chemical plating of high phosphorus nickel → chemical plating of low phosphorus nickel. The key characteristics are as follows: firstly, carrying out physical hole sealing on shrinkage holes by shot blasting treatment before surface treatment of the Al-SiC substrate; secondly, the combination of the chemical plating high phosphorus nickel and low phosphorus nickel processes after shot blasting realizes the corrosion resistance and weldability of the material.

Aiming at the problem of shrinkage cavity of the substrate, shot blasting treatment is added before electroplating, a pneumatic automatic shot blasting machine is adopted, glass shots (the diameter: 0.0331-0.0234 inches), shot blasting intervals are 150-250 mm, and the shot blasting strength is as follows: 0.004-0.008N and 100% coverage rate. The aim of physical hole sealing is achieved through plastic deformation of the aluminum substrate in the shot blasting process, the number of shrinkage holes of the substrate is reduced, and the proportion of qualified substrates meeting the electroplating requirements (no shrinkage holes on the surface of the substrate) is more than 83 percent through visual inspection. After the substrates are subjected to chemical plating of phosphorus and nickel in the conventional process, the surface appearance quality is uniform and consistent, and no tadpole-shaped airflow trace exists. After 96-hour neutral salt spray test according to the GB6458 requirement, the substrate protection level RP reaches GB64615 level, the binding force is detected according to the ASTMB571 specification, and the coating binding force is qualified. After the reflow soldering process is adopted for soldering, the X-ray detection is adopted to find that holes exist on the soldering surface of the substrate and the component, and the soldering wettability is poor.

Further aiming at the problems that the protection level of the substrate is lower than GB 64617 level and holes exist between the welding surface of the substrate and the component, the chemical plating of the medium phosphorus nickel is changed into chemical plating of high phosphorus nickel and chemical plating of low phosphorus nickel, and the corrosion resistance of the substrate and the weldability of the substrate and the component are improved by utilizing the good corrosion resistance of the chemical plating of the high phosphorus nickel and the good weldability of the chemical plating of the low phosphorus nickel. After the substrate is subjected to shot blasting treatment, the substrate is plated by chemical plating high-phosphorus nickel for 60-90 min, and then is plated by chemical plating low-phosphorus nickel for 30-50 min, so that the surface quality of the substrate is uniform and consistent, and no tadpole-shaped airflow marks exist. After 96-hour neutral salt spray test according to GB6458 requirements, the base material protection level RP reaches GB 64618 level, the corrosion characteristics of the plating layer on the surface of the substrate are changed from transverse overall corrosion to longitudinal local corrosion, the integral peeling of the plating layer can be effectively avoided, and the failure of electronic components in the use process is prevented. And (4) detecting the binding force according to the requirements of the ASTMB571 specification, wherein the binding force of the coating is qualified. After the reflow soldering process, no hole is found between the substrate and the soldering surface of the component by X-ray detection.

The formula and parameters of the shot blasting process and the chemical nickel plating process are as follows:

shot blasting: a pneumatic automatic shot blasting machine is adopted. Glass shots (diameter: 0.0331-0.0234 inches), shot blasting spacing of 150-250 mm, shot blasting intensity: 0.004-0.008N and 100% coverage rate.

The high phosphorus nickel process comprises the following steps: NPLF8422A:65ml/L

NPLF8422B:180ml/L

pH:4.6～5.2

Temperature: 85-92 DEG C

Time: 60-90 min

The low-phosphorus nickel process comprises the following steps: DEUTEQ enfinex 666A: 60ml/L

DEUTEQ ENFINIX 666B:150ml/L

pH:5～7

Temperature: 40-80 DEG C

Time: 30 min-50 min.

In the embodiment, the processing object ABB and the Al-SiC surface are coated with an aluminum substrate, the plane size is 137mm and × 127mm, the machining is carried out until the camber of a drawing is achieved, all corners are rounded to R2-3, the number of qualified substrates is 60 after size inspection and visual electroplating, 30 of the qualified substrates adopt the existing process method, and the rest 30 substrates adopt the improved process method.

The prior art mainly comprises the following implementation steps:

organic solvent degreasing → chemical degreasing → acid activation → secondary zinc dipping → phosphorus and nickel in chemical plating for 90 min.

The improved process mainly comprises the following implementation steps:

shot blasting hole sealing treatment → organic solvent degreasing → acid activation → secondary zinc dipping → chemical plating of high phosphorus nickel for 60min → chemical plating of low phosphorus nickel for 30 min.

The Al-SiC substrate is processed by the two process methods respectively, and the appearance of the electroplated coating is detected by visual sampling 100%; extracting 15 pieces of the raw materials for corrosion resistance and binding force detection, wherein the corrosion resistance is more than or equal to grade 7 according to a 96-hour neutral salt spray test RP of GB 6458; the binding force is subjected to a file test according to the requirements of ASTMB571 specification, and a plating layer is not separated from a substrate; the weldability adopts X-ray detection to detect the welding surface of the substrate and the component, and requires that the welding surface has no holes.

The substrate test results were as follows:

obviously, the process of the invention greatly improves the qualification rate.

Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention, and that variations, modifications, substitutions and alterations can be made in the above embodiments by those of ordinary skill in the art without departing from the principle and spirit of the present invention.

Claims

1. A treatment method for improving the corrosion resistance of an AL-SiC substrate is characterized by comprising the following steps: the method comprises the following steps:

step 1: carrying out shot blasting hole sealing treatment on the surface of the AL-SiC substrate; the process parameters for carrying out shot blasting and hole sealing treatment on the surface of the AL-SiC substrate are as follows: adopting a pneumatic shot blasting machine, wherein the diameter of the glass shot is as follows: 0.0331-0.0234 inches, shot blasting distance of 150-250 mm, shot blasting intensity: 0.004-0.008N, and the coverage rate is 100%;

and step 3: chemically plating high phosphorus nickel on the AL-SiC substrate treated in the step 2, and then chemically plating low phosphorus nickel; the technological parameters of the chemical plating of the high phosphorus nickel are as follows: solution ratio NPLF8422A:65ml/L, NPLF 8422B: 180ml/L, pH: 4.6-5.2, temperature: 85-92 ℃, time: 60min to 90 min; the technological parameters of the chemical plating of the low-phosphorus nickel are as follows: solution ratio DEUTEQ ENFINIX 666A: 60ml/L, DEUTEQ ENFINIX 666B: 150ml/L, pH: 5-7, temperature: 40-80 ℃, time: 30 min-50 min.