Lead-free bearing solutions: How to successfully switch to REACH-compliant hydrodynamic bearings

Why was lead used in the first place?

Lead was a key component in many hydrodynamic bearings for a long time. Hardly any other material combines so many functional advantages in one material:

• Excellent emergency running properties:

In the event of insufficient lubrication, lead acts as a lubricant and protects bearings and counter-running partners from damage.

• High embeddability:
Foreign bodies are absorbed into the soft lead layer.

•    Easy handling:
Lead is easy to work with. Materials containing lead can be easily cast, coated, and machined, which simplifies industrial production.

Despite its technical advantages, lead is now considered problematic: Its manufacture, processing, and disposal generate emissions that are harmful to both the environment and human health. For this reason, the use of lead in hydrodynamic bearings is increasingly being restricted, particularly in the automotive, industrial, and aviation industries.

Regulations such as REACH and RoHS mean that switching to lead-free bearing solutions is no longer an option, but will soon be a mandatory requirement.
Miba has been actively involved in the development and manufacture of lead-free bearing solutions for all areas of application for many years.
 

Lead-free does not mean low performance – Miba material expertise

The switch to lead-free materials does not mean compromising on performance or reliability.

On the contrary: modern alloys now offer properties that are equal to or even superior to those of lead-containing materials. This is particularly true when it comes to sliding behavior, wear, and, of course, robustness.

At Miba, our own materials development team has been working continuously for many years on the development and optimization of lead-free solutions.

Miba's lead-free solutions are already in series production. They meet the requirements of many customers in the energy and industrial sectors, are fully REACH-compliant and and geared towards future environmental standards, as only non-critical components are used.

With its in-house test benches, Miba also offers comprehensive testing options for customer-specific requirements, including seizure tests, vibration analyses, and long-term wear tests.

Lead-free bronze hydrodynamic bearing – the proven all-rounder

They have proven themselves over decades, especially under high loads, changing operating conditions, and demanding environments.

Miba relies on a range of lead-free bronzes (InnoAlloy), materials that have proven themselves in numerous tests and customer applications.

Aluminum hydrodynamic bearings – lightweight, stable and lead-free

Aluminum hydrodynamic bearings combine low weight with good tribological properties. This is an attractive solution when weight, friction behavior, and cost efficiency are equally important factors. 

• Lightweight: ideal for weight-sensitive applications
• Very good emergency running properties: especially with aluminum-tin alloys (AlSn)
• Completely lead-free and REACH-compliant
• Inexpensive to manufacture: particularly attractive for large quantities

Miba offers various aluminum-based bearing systems that can be used in both series projects and individual engineering solutions.
 

Plastic hydrodynamic bearings as an alternative? Only to a limited extent.

When inquiring about lead-free hydrodynamic bearings, the question often arises as to whether plastic bearings are a suitable solution. In fact, plastic  bearings offer a number of advantages: they are lightweight, corrosion-resistant, inexpensive to manufacture, and can be used effectively in simple applications with low mechanical and thermal loads.

However, as soon as thermal, mechanical or dynamic requirements increase, plastic bearings quickly reach their limits:

• Lower pressure and wear resistance
• Limited temperature resistance
• Limited service life under continuous load

Conclusion: Lead-free is not a compromise, but progress

The switch to lead-free hydrodynamic bearing is a future-proof decision on several levels: ecologically, legally, and functionally.

Modern lead-free alloys such as Miba's aluminum alloys or the InnoAlloy group show that environmental compatibility and performance are no longer a contradiction. In many applications, they not only meet the requirements of lead-containing bearings, they even exceed them in terms of robustness and corrosion resistance (e.g., in combination with alternative fuels or lubricants).

Plastic bearings may be an option for simple applications, but they reach their limits when the load increases. Metal hydrodynamic bearings from Miba, especially those made of aluminum alloys or bronzes, preferably in lead-free versions, offer the necessary safety and performance.