The CrNi layer offers very good wear protection in combination with high corrosion protection. Here, all the advantages of hard chrome and electroless nickel are being combined in one coating system. This combination layer meets the highest demands and is ideally suited for the use in an environment with high chemical and mechanical stress.
The CrNi layer system
In hybrid coating, components are first electroless nickel-plated and then hard chrome-plated. The combination layer guarantees very good wear protection in conjunction with strong corrosion protection and high chemical resistance. Due to its functional properties, the hybrid coating is ideally suited for use in an environment with high chemical and/or mechanical stress.
The layer thicknesses are based on the technical requirements, e.g. 0.030 mm electroless nickel and 0.040 mm hard chrome.
To improve the coating adhesion, we recommend a heat treatment of the components as an intermediate step after electroless nickel plating. The components are tempered in a furnace between 230°C – 400°C. The thermal post-treatment increases the adhesion of the electroless nickel layer. Tempering also increases the hardness of the electroless nickel layer to about 1000 (± 50) HV and improves the wear behavior.
Properties of your components
- Base material: all steels and non-ferrous metals
- Maximal dimensions: ⌀ 600 x 1100 mm
- Maximal Weight: 250 kg
In hybrid coating, the electroless nickel layer provides corrosion protection that is closed on all sides and the hard chrome layer ensures high hardness without distorting the material. The low coefficient of friction confirms the anti-adhesive properties of the chrome layer. This describes the behavior of chrome surfaces to repel aqueous media and dirt. This ability also increases the corrosion resistance of hard chrome surfaces. A further advantage is the micro-cracked structure of the hard chrome layer, which absorbs applied lubricants well for wear protection. The fine network of cracks also increases the ductility of the chrome layer, making it less brittle in relation to its high hardness.
- Layer thickness: depending on requirements e.g. 0.030 mm electroless nickel and 0.040 mm hard chrome
- Roughness: Rmax < 0.1 μm to Rz 70 μm
- Hardness: 1000 ± 50 HV 0.1
- Corrosion resistance according to DIN EN ISO 9227-NSS: > 480 hours
- Expansion coefficient: 6.6 to 8.4 x 10-6 1/K
- Ductility: 0.1% elongation at break
- Wear resistance: < 5 mg/1000 revolutions
- Coefficient of friction: 0.15 lubricated or 0.21 dry against steel
- Tensile strength: 280 to 450 N/mm²
- Lead and cadmium free (RoHS compliant)
For orders with increased time pressure, you have the option of using our express service. The express service is coordinated directly with our production control and invoiced via a surcharge.
Before the start of more complex series, we offer you an initial sampling at special conditions. This allows you to convince yourself of the quality of our services. In addition, together we coordinate our production processes ideally.
Tips for the delivery
The delivery condition of the components is one of the decisive factors for optimum coating quality and a short throughput time. Here you will find helpful tips for the delivery of your components.
Betz-Chrom – your partner for strong parts
In the sense of a trustful partnership, you will receive highly qualified technical advice from us that is tailored to your needs. We combine over 65 years of experience in surface technology with an innovative and inquisitive corporate culture. Our quality awareness, our occupational health and safety management as well as our measures for environmental protection and energy saving are audited and certified according to DIN standards. As an on-schedule partner with high quality level, we constantly aim to find the optimal process solution for you.
This post is also available in: German