# Read powder specifications with confidence Source: https://powdchem.com/resources/ Page type: Sourcing knowledge Sourcing knowledge Use these examples to compare material descriptions, size results and technical documents. The exercises explain the information; they do not describe available Nike grades. [Choose a topic]() [Ask about your requirement]() ## Preparing a powder specification Begin with the material and the process. Mark each requested value as essential, a preference or still unknown. This makes it easier to discuss a candidate without treating every blank as a requirement. | Part of an example AlN brief | How to write it | | --- | --- | | Identity | Aluminum nitride (AlN), dry powder; any required surface treatment stated separately. | | Essential requirement | Insert the particle or impurity limit your process requires, together with the test method. | | Preference | A preferred pack size or delivery date that can be discussed. | | Unknown | A property you need help defining; leave it open rather than adding an arbitrary number. | This is a teaching example, not a specification for an available AlN grade. ## Reading purity and impurity information A percentage is useful only with its reporting basis. Check whether the result describes the whole material, a metals-only calculation or another defined scope. Then look at the individual impurities that matter to your process. | Teaching example | What it leaves open | | --- | --- | | Candidate A: “99.9% purity” | The calculation basis, methods and individual impurity results are not stated. | | Candidate B: “99.8%”, with an impurity table | The table may be more informative, but the calculation basis and methods still need to be compared. | | Your decision | Ask for comparable definitions and critical impurity limits before ranking the percentages. | The percentages above are invented for this reading exercise and are not Nike supply specifications. ## Reading D10, D50 and D90 First find the distribution basis and method. A volume-based result describes proportions of particle volume; a number-based result counts particles. Keep these bases separate when comparing reports. Diagram: Teaching example: cumulative undersize by volume. Dv10 is 1 micrometre, Dv50 is 5 micrometres and Dv90 is 12 micrometres. Read across, then down ### A percentile is a cut-off. **Dv10 = 1 µm:** 10% of the particle volume is below 1 µm. **Dv50 = 5 µm:** 50% is below 5 µm. This is the volume median. **Dv90 = 12 µm:** 90% is below 12 µm. This is not the largest particle. Teaching example, not a grade specification. Keep the measurement method and dispersion conditions with the values. | Volume-based teaching example | How to read it | | --- | --- | | Dv10 = 1 µm | 10% of the measured particle volume is below this size. | | Dv50 = 5 µm | 50% is below this size: the volume median, rather than an arithmetic average. | | Dv90 = 12 µm | 90% is below this size. It is not a maximum particle-size limit. | These figures are teaching values, not a material grade. The same Dv50 can occur with different fine and coarse fractions. Check Dv10 and Dv90 as well as the measurement and dispersion conditions. For sheet powders, keep platelet width and thickness separate from a powder distribution that may include agglomerates. ## Separating chemistry, crystal phase and shape The formula answers “what is it made of?” Phase and shape answer different questions. Keep all three when the process depends on them. | Example | What to identify | | --- | --- | | BN | The boron nitride chemistry. | | h-BN versus c-BN | The required crystal form, even though both use BN as the formula. | | BN nanosheets versus ordinary powder | The requested sheet morphology, lateral dimensions and thickness, with evidence tied to the candidate. | | A coated or treated powder | The core material and the treatment, rather than the core formula alone. | Use microscopy or phase-identification records that actually describe the proposed grade or sample. A product name alone does not establish its dimensions. ## Using COA, TDS and SDS together Start by matching the product name, code and supplied form across the documents. Then check which question each document answers. | Document | Useful question | Check before using it | | --- | --- | --- | | TDS — technical data sheet | What does this grade typically look like? | Version, measurement basis and whether a number is typical or a specified limit. | | COA — certificate of analysis | Which results are reported for the identified material or batch? | Material identity, applicable lot, tested parameters and methods. | | SDS — safety data sheet | What handling and hazard information applies? | Exact material, supplier information and current revision. | Example: a TDS with typical particle size does not fill a missing particle-size test on a batch COA. Ask for the applicable test or agree whether the available evidence is enough for evaluation. [Use the document comparison tools]() ## Writing a ceramic processing brief A chemical formula is only one part of the feedstock. Describe the material state needed at the start of your process. | Your process starts with | What belongs in the brief | | --- | --- | | Loose powder for your own mixing | Phase, particle distribution, surface area where needed, impurities and any treatment. | | Granules for a forming step | Granule characteristics, binder or additive requirements and the forming route. | | A slurry or prepared formulation | Liquid or binder system, solids content and the supplied formulation requirements. | Keep powder acceptance separate from tests on the fired part. Record the forming and firing conditions behind any final-part result. [Explore ceramic processing tasks]() ## Comparing solid-electrolyte information Use the composition, dopant and phase first. Then compare conductivity data only with the specimen and test conditions that produced it. | Same reported property | Questions that change the comparison | | --- | --- | | Ionic conductivity | What temperature, specimen density and measurement method were used? | | Pressed or fired specimen | What pressure, sample preparation or sintering process was used? | | A material for your cell experiment | Which electrode configuration, atmosphere and interface preparation will you evaluate? | Two different preparation methods may produce results that cannot be ranked as a simple grade comparison. Keep those differences visible in the sample plan. ## Connecting a sample to a repeat order Keep the sample identity and your evaluation record. For a repeat requirement, compare the next proposed material against the acceptance conditions agreed for the order. | Record to retain | Why you need it | | --- | --- | | Sample product code and lot, if provided | Identifies the material actually evaluated. | | Recipe, preparation and test conditions | Lets the next evaluation use a comparable process. | | Accepted limits and any exceptions | Separates essential requirements from observations and preferences. | | Proposed order grade and batch documents | Shows which records apply to the next material, rather than silently reusing the sample result. | [Plan samples and testing]() ## Build your own material brief Use the blank template to record known requirements and open questions. [Download the blank brief]()