This study focuses on the corrosion prevention of the heat sink surface through the use of anti-corrosion coatings. The heat sink terminal, which is generally made of steel, is easily corroded when exposed to the environment. In this project, the heat sink sample is made from Eco-Trio steel (or known as ZSNC steel), one of Nippon Steel's products.
This rusted terminal will resist any soldering fluid, which means the heat sink terminal will not mate perfectly with the copper board. The literature review is divided into three parts which are the study on corrosion, heat sink and anti-rust coatings. Finally, this project should be a useful addition to understanding corrosion in the cooler terminal and its prevention using anti-rust coatings.
Consequently, the outcome of this project should offer benefits to all parties involved; especially the student himself. 57 Appendix D: Result of Monitoring Activity for Simulated Condition 63 Appendix E: Result of Monitoring Activity for Simulated Condition 65 Appendix F: Pictures of Heat Sink and Heat Sink Terminal.
INTRODUCTION
Background of Study
- Confidence level of recurring problem 2
From an economic point of view, the Antirust Coating method is better because it costs less than the Change Packaging method. The heatsink connection must be free of any surface corrosion to ensure that no pinhole problems occur during immersion in soldering fluid. The investigation of the heat sink terminal takes a few weeks because some circumstances must be taken into account, such as the material used, the production process and the storage conditions.
To continue the project, the confidence level of recurring problems has been taken into account. In 2007, more than 50,000 heat sink units were rejected due to corrosion problems. Rust on the terminal affects the soldering process and often causes pin-hole problems because it is resistant to soldering fluid (see Appendix A).
To overcome these problems, this project was proposed to find optimal anti-rust coatings. This will prevent corrosion problems on the heatsink terminal surface and also does not resist the soldering process.
Objective of study
Scope of study
LITERATURE REVIEW
Corrosion
- Definition of Corrosion
- Mechanism Of Corrosion
- Selecting Materials for Corrosion
- Environment
- Corrosion Rate Expressions
The flow of electricity from one metal to another or from one part of the metal surface to another part of the same metal surface where conditions allow the flow of electricity causes corrosion in metals. Therefore, if corrosion is to take place in a metal, there must be an electrolyte, an area or region of the metallic surface with a negative charge relative to another area with a positive charge opposite to the first area. It can flow between a metal and some kind of metal receptacle, such as the earth, or between two different metals.
If the soil is negative for the metal and an electrolyte such as water is present, corrosion of the metal will occur (p.12). This is indicative of good corrosion resistance, and metals in this category may be considered for critical parts such as springs, valve seats, pump shafts, etc. Once a preliminary selection has been made based on the suitability of a specific material to resist system corrosion, the following parameters for the materials are taken into account, see figure 2-3 and figure 2-4.
Corrosion of iron or steel is usually determined by the environment and also the stability of the oxide layer on the surface. The penetration rate or thinning of the structural piece can be used to predict the service life of a given component.
Heat Sink
- Triple Coated Steel – Ecotrio . 13
- Construction and Materials
The efficient operation of a cooler relies on the rapid transfer of thermal energy from the first object to the heat sink and from the heater to the second object. Tillmann Steinbrecher points out that “the most common design of a sink is a metal fixture with many fins. This design method cools the coolant and anything with which it is in direct thermal contact.
Likewise, a fan can improve the transfer of thermal energy from the heat sink to the air. This goal can be achieved by using a large amount of fine fins, or by increasing the size of the heatsink itself. Of course, the material used has a great influence on thermal transfer within the cooler.
The part of the heat sink that is in contact with the heat source must be completely flat. For good thermal transfer, the pressure between heat sink and heat source must be high. While a heatsink is a static object, a fan often aids a heat sink by providing increased airflow over the heatsink.
The heat sink's contact surface must be flat and smooth to ensure the best thermal contact with the object to be cooled. This project deals with the study of corrosion, heat sink and anti-rust coating that must be applied to steel surfaces to prevent corrosion. The research also focused on heatsink, as heatsink is also the main topic in this study.
Heatsink research has been mainly on the construction material used for the heatsink body and terminal. This test essentially shows the effect of anti-rust coatings on the heat sink terminal surface, regardless of whether the coating interface is a solder process or not. The coated heatsink terminal has been mounted on the printed circuit board and is going through a machine soldering process.
The main purpose of this project is to select the best antirust to be used to cover heat sink terminal. Solder probably won't stick to the coated heat sink surface because the coating is too thick. The selected antirust can protect heat sink terminal surface by providing a clear layer of barrier on the surface.
