Surface Finishes

OptiMIM provides customized surface finishes, plating & coating services tailored to the specific requirements of each component. Our MIM materials can be readily plated or surface treated with standard processes used on wrought materials with no need for special surface preparations.

Surface Finishes for Metal Injection Molded Parts



Chrome finishes are widely used for various applications to improve aesthetics and enhance functionality. Due to its durability, chrome is well-suited for parts exposed to friction. It is commonly employed in medical devices and equipment due to its sterile properties, although it is also used in the automotive and firearms industry.


Electroless Nickel

The key element of an electroless nickel finish lies in its ability to generate a corrosion-resistant layer. Nickel plated parts typically fall within sectors including electronics, tooling, and automotive industries

Heat Sink: Automotive

Black Oxide

This finish is a type of conversion coating where the part’s surface is transformed into black oxide to provide corrosion and wear resistance. This coating is commonly used in the firearms industry, among others.
GSM Follower: Consumer Electronics 


Physical Vapor Deposition (PVD)

The PVD process is a technique used to create hard metal-based coatings for wear resistance and/or cosmetics. Applications include firearms, medical devices, cutting tools, and other sectors that find advantages in both durable and decorative characteristics. 

Physical Vapor Deposition Lever Part for a Firearms Product

Lever: Firearms 

Phosphate (Parkerizing)

This finish is a type of conversion coating that interacts with the base alloy. The automotive and machinery industries utilize both manganese and zinc phosphate for corrosion protection and lubrication. Manganese phosphate is generally classified as a Mil-Spec (military specifications), or military grade surface finish, and is frequently applied to various defense industry applications.

Ferritic Nitrocarburization (Melonite)

This is a conversion coating where it transforms the surface of the part into an iron nitride compound and leaving an incredibly hard surface finish. The compound layer created is resistant to wear and corrosion. The layer created is durable enough to have a Vickers hardness of about 800 to 1500 HV depending on the material used.

Bolt End Cap: Firearms 

Tumble Polishing

This technique employs porcelain or an aluminum oxide polishing media to achieve optimal smoothness without the need for hand polishing. Engineers at OptiMIM have been able to achieve 16 micro inches with this process. 

After the tumble polishing process, parts can be sent for double disk grinding for additional benefits including increased material removal and improved dimensional accuracy as seen demonstrated below.
Tumble Polished and Ground Firearms Trigger Disconnect: Firearms

Media Blasting

Media blasting uses a smaller media size than tumble polishing. One media blasted finish involves glass beads, which are small glass spheres that produce a glossy finish. Mined and classified aluminum oxide grit serves as an alternative to media blasting, creating a matte finish. A satin finish combination can be achieved by blending both glass beads and aluminum oxide grit. 

Glass Bead Media Blasted Surgical Instrument: Medical Devices and Equipment 





Hot Isostatic Pressing is a post-casting treatment that improves the internal structure and mechanical properties of castings. This process, involving high pressure and elevated temperature in a specialized chamber, closes internal voids or porosity, enhances strength, fatigue resistance, and ductility. HIPing also stabilizes casting dimensions, reduces distortion, and ensures greater precision in the final product. 



The surface of a part remains unchanged as it comes out of the furnace through the as-sintering process. Laser texturing is applied directly to the tool to imprint a textured pattern onto the part. 

As-Sintered Armature Blank  

For more information on our surface finishes, contact one of our experts today.


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Last updated 02.03.2022