How to Select High-Purity Spherical Colloidal Silica? Features and Technical Specifications of the DMAC-SP Series | DMAC


In applications such as precision polishing, electronic materials, and related surface treatments, the particle size uniformity, dispersibility, purity, and sphericity of colloidal silica significantly influence process stability and the quality of the final surface. The DMAC-SP series consists of spherical SiO2 particles, with particle sizes that can be customized to meet specific customer requirements. Because a single purity metric is insufficient to determine suitability, selection should be based on a comprehensive evaluation of particle size distribution, dispersion state, polishing performance, impurity requirements, and the specific demands of the actual process.


## Why Focus on Particle Size Uniformity and Sphericity?


1. Uniformly sized, spherical SiO2 particles contribute to more consistent polishing behavior.
2. Excellent dispersibility minimizes the risk of agglomeration and sedimentation, facilitating ease of use in industrial processes.
3. High purity reduces the risk of introducing unwanted components; however, specific levels should always be verified against batch-specific test data.
4. Sphericity, which reflects the consistency of particle morphology, is a key indicator for evaluating spherical colloidal silica.
5. While particle sizes can be customized, each specific size specification requires individual validation regarding its dispersion characteristics and polishing performance.
6. Low radioactivity is a key product feature; specific levels should be confirmed via the test report for the relevant batch or through the agreed-upon technical specifications.


## Features of DMAC Colloidal Silica


The DMAC-SP series of colloidal silica is characterized by uniformly sized spherical SiO2 particles, excellent dispersibility, stable polishing performance, high purity, and low radioactivity. Particle sizes can be customized to meet customer requirements. Product grades—such as "DMAC-SP-Custom"—may include specific numerical designations or suffixes, which are determined based on particle size specifications, packaging requirements, and the agreed-upon technical supply agreement. ## Technical Specifications


| Parameter | Typical Value | Notes |
|---|---:|---|
| Purity (SiO2) | ≥99.999% | Subject to product technical specifications and batch test reports. |
| Sphericity | ≥99.0% | Indicates the morphological consistency of the spherical particles. |
| Particle Size | Customized to requirements | Requires confirmation of target particle size, distribution specifications, and application process. |
| Dispersibility | Characteristic property | Must be verified based on the actual medium and usage conditions. |
| Polishing Performance | Characteristic property | Evaluated through polishing tests using samples. |
| Low Radioactivity | Characteristic property | Subject to batch testing or specific technical agreements. |


## Grade Designation


The "DMAC-SP" series serves as an example of the grade designation system for DMAC’s spherical SiO2 products (derived from silica sol). As no fixed particle size specifications are provided in the source text, specific numerical values within the grade name should not be assigned arbitrarily. Options include using "DMAC-SP-Custom" or establishing a specific grade designation through mutual agreement between the supplier and the buyer, based on "particle size specification + packaging format + technical agreement." In cases where information is incomplete, it is not advisable to determine a final product model based solely on "high purity" or "high sphericity."


## What information should be confirmed before procurement? | Information Category | Details to Confirm |
|---|---|
| Particle Size Requirements | Target particle size, particle size distribution range, and allowable deviation |
| Purity Requirements | SiO2 purity, controlled impurity elements, and testing methods |
| Morphological Requirements | Sphericity (degree of spheroidization), roundness, and control of agglomeration |
| Dispersion System | Dispersion medium, solids content, pH, and stability requirements |
| Application Process | Material being polished, equipment, concentration, circulation method, and temperature |
| Downstream Processes | Cleaning, filtration, storage, and compatibility with existing materials |
| Test Reports | Batch-specific data, including purity, sphericity, particle size, and low-radioactivity levels |
| Packaging and Storage | Packaging specifications, shelf life, and transport/storage conditions |


## How to Conduct Sample Validation?


1. Ensure consistency in polishing equipment, process parameters, and substrate batches.
2. Set up a comparative test between the currently used colloidal silica and the DMAC-SP candidate sample.
3. Keep concentration, flow rate, polishing pressure, rotational speed, and processing time constant.
4. Observe and record the dispersion state, as well as any signs of agglomeration, sedimentation, or filtration issues.
5. Compare polishing rates, surface roughness, the presence of scratches, and the ease of cleaning.
6. Verify compatibility for products that require further downstream processing.
7. If necessary, analyze particle size distribution and sphericity to confirm alignment with the supplier’s specifications.
8. Use the stability of continuous operation and batch-to-batch consistency as the final criteria for selection.


The DMAC-SP series of colloidal silica offers high-purity, spherical SiO2 particles with customizable particle sizes. However, actual suitability should be confirmed based on the specific grade, batch test reports, and the results of process validation.