Boron Nitride Coatings Are Mainly Used For Mold Release in The Aluminum Industry

In casting, extrusion and die casting production of aluminum and aluminum alloys, mold release has been a key challenge affecting production efficiency and product quality. Traditional mold release agents (such as graphite, silicone oil, etc.) there are pollution, residue and high temperature failure and other problems, and boron nitride (BN) coatings by virtue of its excellent high temperature resistance, self-lubricating and chemical inertia, is becoming the aluminum industry, the new choice of mold release technology.
I. Advantages of boron nitride coatings for mold release
1. Ultra-high temperature stability (temperature resistance >1500℃)
Boron nitride coating will not oxidize or decompose during aluminum alloy die casting (600-800℃) and fusion casting (1200℃+), which is far better than graphite (>500℃ oxidation) and silicone mold release agent (<300℃ failure).
Case: After an aluminum wheel factory adopted BN coating, the mold life was extended by 3 times.
2. Extremely low coefficient of friction (μ<0.2)
The layered structure of h-BN provides graphite-like lubricity without the risk of carbon contamination.
It reduces the adhesion of aluminum liquid to the mold and reduces the release force by 30-50%.
3. Zero Pollution & Easy Cleanup
BN does not react with aluminum, avoiding impurities on the casting surface (e.g. silicon residue) caused by traditional mold release agents.
The coating can be used for a long time, reducing the downtime of frequent spraying of mold release agents.
Typical application scenarios
1. Aluminum alloy die casting (automotive parts, 3C shell)
Problem: High-silicon aluminum alloy (such as ADC12) is easy to stick to the mold, the traditional mold release agent needs to be sprayed once every 5-10 mold times.
Solution: The mold surface is coated with BN coating (10-20μm), which can be used continuously for more than 200 die times without re-coating.
2. Hot extrusion of aluminum profiles
Problem: Wear and tear of the extrusion barrel and die cause scratches on the profile surface.
Solution: Adopt BN-based lubrication coating to reduce friction and improve surface finish (Ra<0.8μm).
3. Aluminum alloy fusion casting (flat ingot, round bar)
Problem: Aluminum bonding on the inner wall of the crystallizer, leading to cold segregation and cracks.
Solution: BN coating replaces graphite coating to reduce ingot surface defects and increase yield by 15%.
Boron nitride coating is reshaping the aluminum industry's release process through its high temperature resistance, self-lubrication, and zero-pollution characteristics, especially in high value-added areas (such as automotive lightweighting, electronic shell die casting) to show great potential. With the advancement of large-scale production and coating technology, BN coatings are expected to become the mainstream solution for replacing traditional mold release agents.