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Ferrite Core Grinding: A Guide

March 9, 2023

Ferrite is a metal compound that manufacturers use to produce magnetized ceramic for signal transformers, power transformers, speakers, and other electric or electronic goods. Ferrite contains iron oxide as well as other metals like barium, nickel, or zinc.

At Quartzite Processing, we grind and machine ferrite magnets for manufacturers around the world, with ship-to-stock and just-in-time delivery capabilities to meet your deadlines. Our company is ISO 9001:2015 certified and ITAR registered, and we have been serving our clients with high-quality machining and grinding services for over 65 years.

Ferrite Core Manufacturing Process

There are four key stages in manufacturing ferrite cores to produce high-quality materials for future products.

Powder Preparation

First, manufacturers create the ferrite powder—a carefully measured blend of iron oxide and other elements. The powder mixture is determined by weight and is held to extremely high purity standards; even slight fluctuations in purity can significantly impact the finished product.

Manufacturers can use two different mixture processes:

  1. Dry mixing: The powders are mixed without any additional moisture until it creates a homogeneous material.
  2. Wet mixing: Manufacturers add water and mix the powder into a homogeneous slurry. Then, the mixture undergoes drying to remove excess water.

Next, manufacturers calcine the powder mix, or pre-fire it in an oven with air temperatures of 1000 °C, which removes some impurities without breaking down the desired carbonates and oxides in the mixture. After this stage, manufacturers add water and mill the resulting slurry to create a compound of consistently sized particulates. Then, manufacturers add binders and lubricants before drying the slurry.


In this stage, manufacturers form the particulate material into the final product shape. Processes such as dry pressing, isostatic pressing, or extruding pack the particles together in the desired form using pressure and pre-made molds.

Isostatic pressing is commonly used for prototype development, whereas extrusion produces long forms with a small cross-section. Dry pressing can form a wide variety of shapes, but the pressing process only operates along the vertical axis, allowing for limited adjustments.

Sintering Process

This stage gives ferrite cores their magnetic properties, and it is a very sensitive process. Manufacturers start by slowly raising the temperature of the kiln containing the ferrite cores to approximately 800 °C to remove impurities. Then it is heated up to 1500 °C, where nickel-zinc ferrites begin to sinter. Manufacturers also introduce nitrogen into the kiln to reduce oxygen content and enhance the final product quality.

Ferrite Finishing

After sintering is complete, the composition of the core is set. However, manufacturers can optimize the core’s performance with finishing processes, such as:

  • Gapping
  • Coating with parylene, nylon, or epoxy
  • Lapping to minimize air gaps
  • Grinding

What Should You Look for in Ferrite Core Grinding Service Providers

Finding the right service provider for high-quality ferrite core grinding can make all the difference. As you search for grinding services, look for manufacturers that have these characteristics:

  • Expertise: Do they specialize in grinding ferrites or ferrite magnet production? How many years of industry experience do they have?
  • High-quality raw materials and standards: Look for companies that can offer the precise ferrite compound mixtures your organization needs and maintains high purity standards.
  • The right production capabilities: Look for organizations that offer the production volumes you need now and as your business grows.
  • Prompt customer support: Are they responsive? Are their answers helpful? Try to look for a supplier who offers prompt, accurate customer service through in-house staff.

Hard Ferrites vs. Soft Ferrites: What Are the Differences?

Ferrites fall under two major categories: hard ferrites and soft ferrites.

Soft Ferrites

Soft ferrites can be easily demagnetized in the presence of an external magnetic field. They have low coercivity and act as conductors. Some of the use cases for soft ferrite include EDP equipment, antennas, inductors, microwaves, and transformers.

Hard Ferrites

Hard ferrites can be exposed to external magnetic fields without demagnetizing; they have high coercivity. Because their magnetic field is more durable, hard ferrites can be used in more complex applications. These include clocks, DC motor rotors, industrial electronics, sensors, radios, and appliances.

Benefits of Ferrites

Ferrite cores are beneficial materials for electrical and electronic products. They can prevent eddy currents due to their high permeability and low conductivity characteristics, making them particularly useful for RF transformers. AM radio receivers also benefit from the lack of eddy currents, so ferrite toroids are commonly used here.

Ferrite Machining From Quartzite Processing Inc.

Choosing the right ferrite core grinding company ensures you have the right ferrite—with the right material composition and purity level—for your manufacturing needs. Quartzite Processing specializes in the grinding process of ferrite magnets, producing them with precise shapes and finishes for a wide range of applications. Our precision grinding services are also ideal for creating millimeter-wave ferrites used in millimeter-wave technology.

Learn more about our ferrite machining capabilities, or contact us today with questions. Request a quote to start your order.

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