MIM Materials

Table of Contents

• Common MIM Materials

• BRM Materials

• Customizing MIM Materials

• MIM Material Options

• MIM Material Applications

• General material properties

• MIM material properties

• Mechanical properties

• Fatigue strength and fracture toughness

• Corrosion Resistance

• Biocompatibility

• Wear Performance

Common MIM Materials

Metal Injection Molding produces a variety of high performance, complex geometry parts without additional processing. Due to the high density of MIM parts, their performance is comparable to other manufacturing methods. The flexibility of material selection is high, and the same equipment can be produced from different metal materials. In addition, a variety of metals can be used in the MIM process. Metal powders with various chemical compositions, particle sizes and shapes will determine the final performance of MIM parts. In summary, our MIM materials are divided into the following categories.

Ferrous alloys: steel, stainless steel, tool steel, low-alloy steel, iron-nickel alloys, special iron alloys such as Yin steel and Corvair iron-nickel-cobalt alloy.

Tungsten alloys: tungsten copper, tungsten heavy alloy.

Nickel alloys: nickel, nickel-based high-temperature alloys.

Molybdenum alloy: molybdenum, molybdenum-copper.

Titanium alloy: titanium, titanium alloy.

Hard materials: cobalt-chromium, cemented carbide (WC-Co), cermet (Fe-TiC).

Specific materials: aluminum, precious metals, copper and copper alloys, cobalt-based alloys, magnetic alloys (soft and hard), shape memory alloys.

BRM Materials

You can view our common MIM materials as shown below.

Customizing MIM Materials

Most alloy compositions are copied from standard manual recipes. However, it cannot be overlooked that long annealing during the sintering process reduces the alloy properties, as most alloys are created and developed in the casting technology. Therefore, BRM uses chemical modifications in the MIM technology to ensure the physical and chemical properties of MIM parts.

For example, the 316L alloy composition (Fe-19Cr-9NI-2Mo) is widely used due to its corrosion resistance and combined strength properties. Otherwise, the additional chromium in the alloy composition will make the sintering process easier, so this alloy offers excellent properties obtainable through this alternative metal fabrication method.

Once the composition is not available, custom metal powders can be manufactured at an additional cost. There is no doubt that BRM will meet any of your custom material requirements at the most cost effective price.

MIM Material Options

MIM Material Applications

We need to consider many factors to select the ideal material for MIM parts, such as MIM part weight, tolerance requirements, mechanical stress, hardness, additional machining, maximum cross-section, corrosion resistance, etc.

BRM offers common MIM materials for the following different applications: Click here to view our detailed MIM material properties.

General material properties

For custom MIM part requirements, we also provide you with the mechanical properties of conventional MIM materials, as shown in the following table.

MIM material properties

The sintered density of MIM products is approximately 98% lower than the theoretical density, so the MIM sintering process will affect the chemical, physical, elastic and thermomechanical properties compared to the brochure information.

BRM's goal is to provide our customers with high quality MIM parts, so we consider the impact of materials during the MIM sintering process. It will help our engineering team to provide multiple treatment recommendations for your project.

Mechanical properties

MIM technology products have the same tensile properties as other manufacturing routes.

Fatigue strength and fracture toughness

For high toughness metal materials, we never need to worry about this issue. However, in other cases, material testing is recommended because MIM has a large grain size and residual porosity.

Corrosion Resistance

Stainless steels using the MIM method can cause corrosion resistance problems because the preferential surface evaporation of chromium during the sintering process can reduce corrosion resistance. However, with proper post-sintering and surface treatment, the final MIM part can perform well in terms of general corrosion resistance to a variety of media.

Biocompatibility

MIM parts are increasingly being used in medical and dental applications, so biocompatibility is becoming comparable to other pathways. In this case, post-sintering and electrochemical treatments are required to re-homogenize the surface chemistry of the MIM part to achieve biocompatibility.

Wear Performance

In the MIM process, mixing hard phases into the raw material will improve the wear behavior of MIM parts. For example, MIM tool steels treated with low concentrations of calcium difluoride have a significantly higher dry wear rate than forged tool steels. The addition of titanium nitride or chromium boride to stainless steel will improve the wear resistance of the final product.

BRM is able to meet the standard published by the Metal Powder Industries Federation (MPIF): MPIF Standard 35, Material Standard for Metal Injection Molded Parts - 2018 Edition. This is the most comprehensive standard covering all aspects of the metal injection molding industry.