# What is Powder: Definition and 85 Discussions

A powder is a dry, bulk solid composed of many very fine particles that may flow freely when shaken or tilted. Powders are a special sub-class of granular materials, although the terms powder and granular are sometimes used to distinguish separate classes of material. In particular, powders refer to those granular materials that have the finer grain sizes, and that therefore have a greater tendency to form clumps when flowing. Granulars refers to the coarser granular materials that do not tend to form clumps except when wet.

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1. ### Powder coating: way to add more positive charge?

I am thinking of powder coating at home. I know the part to be coated is negatively charged because it is grounded. I assume the powder is positively charged by the gun. I wonder if there is a way to add more positive charge cheaply to an inexpensive gun like the one at harbor freight? I think...
2. ### Is it Safe to Use Garlic Powder When Grilling Meat?

When using garlic powder in recipes, is it important to avoid toasting it? Videos about cooking with fresh garlic caution about not burning the garlic. When no water is present in a pan, they generally show heating fresh garlic for only a few seconds after it is added. Then you must add a...
3. ### Working out Plane Structure via Powder X-ray Diffraction Multiplicand

Below is the measured values for the Debye rings I obtained. I have to multiply the ratio (which is (sin^2(theta_n))/(sin^2(theta_min))) by a multiplicand until I get an integer. However for the multiplicand and the values I measured I get 1, 3, 13, ??, 4, 8, ??. These should either correspond...
4. ### Dishwasher and a white powder residue

I put a knife at bottom of the dish washer, and this was the result after 2 hour cleaning and drying time (just rarely though). What is the white powder? Is it the salt? The soap? scales from hard water? Or dried rinse aid? I recently acquired dish washer. It seemed to clean the dishes and...
5. ### Free Falling powder in a vacuum

I made experiment on "Free Fall". I made a conical hopper of 15 liter volume and a vacuum chamber of , installed hopper upon vacuum chamber of 65 liter volume. Fixed a 2.5" gate valve to discharge powder in vacuum chamber. Connected both, hopper and vacuum chamber to vacuum pump (63 cum/ hr) and...
6. ### Insulated copper wire turned into gray powder

Summary: Insulated copper wires (not plated) inexplicably turned into gray powder. Wires are intact between affected spots. This is a piece of common red/black loudspeaker cable, with PVC insulation, pulled from service after about 18 months from installation. It was used to feed a small...
7. ### Can Pyrotechnic Pepper Spray Be an Effective Non-Lethal Weapon?

Hello. Ordinary pepper sprays on the market are cans pressurized with propane, butane etc., that propells the liquid pepper through a spray nozzle. So I thought, would it be possible to make a pyrotechnic composition that act as pepper spray? Either that the burning powder itself act as a...
8. ### A Powder XRD sample prep question

Hello, I have an unusual case in that I am using XRD to study plant skins before and after certain chemical treatments. So the resulting pattern will have a lot of amorphous regions but also some characteristic peaks showing the presence of fatty acids, etc. Basically I grind everything to a...
9. ### Is neodymium powder as strong of a magnet as solid neodymium

In attempting to make magnetized neodymium powder, I grinded neodymium magnets into a powderusing a belt sander. However, I found that the magnetic properties of the neodymium had decreased substantially. It would appear that any attempt to grind the magnets into a powder using this method seems...
10. ### Powder sample crystal is analyzed using Debye-Scherrer method....

Homework Statement Powder sample of monoatomic cubic lattice crystal is analyzed using Debye-Scherrer method. Primitive vetors of direct lattice are: a1 = (a, 0, 0), a2 = (0, a, 0) i a3 = (0, 0, a). Wavelength of x-ray radiation is 1 Å. a) Find primitive vectors of reciprocal lattice. b) Find...
11. ### A What is the best free software for analyzing powder XRD data?

I studied an elementary course as an introduction to Solid State Physics. Now I have powder XRD data to practice crystal structure determination. I am going to do this alone in my computer. I want to know what software to use (free software) with manual of course. Any help please?
12. ### News J&J knew about asbestos in baby powder

J&J shares plunge 11% after report that the company knew for decades about asbestos in baby powder https://www.cnbc.com/2018/12/14/johnson--johnson-shares-drop-on-reuters-report-that-the-company-knew-for-decades-of-asbestos-in-its-baby-powder.html Is it inherent that asbestos is in talc powder...
13. ### Seeking White Powder Alkali Indicator (that can take 900°C)

Hello all! I'm doing some research for a project I have and I need to try and source an indicator which is white/bland in colour when dry and is quite vivid in colour when in an alkali solution. The solution in question is a ceramic slurry, which has a PH of between 9.5 and 10. The aim is for...
14. ### Suspending Chrome oxide polishing powder

Hi, In new to this forum, but I need help on mixing .5 micron chrome oxide powder. Into a liquid so I can put it into a mini spray bottle to apply to a leather or balsawood substrate for polishing steel. I was reading online about examples of different things being mixed together for example...
15. ### I Question about Powder X-ray diffraction experiment

I don’t understand why do we use power in this experiment. If we use powder, the d spacings of each crystalline will be oriented randomly, why won’t the angle of reflection changes? I don’t understand the idea of using powder in the experiment. Thank you so much
16. I

### B How can one turn diamond powder back into hard stone form

I have some diamond powder and was wondering how I can turn it back into its hard stone form? What can I do. I'm a hobbyist chemsit/physicist. I just need some help from more knowledge people
17. ### Ar (Gas) goes into spinner (Adiabatic Decompression): Power?

Homework Statement Argo, in its gas form, is insterted into a spinner, with a rhythm of 80.0 kg/min = 1.33 kg/s, temperature 800 C (= 1073.15 K), and pressure 1.50 MPa. It's decompressed adiabatically, and "escapes" the spinner with pressure 300 kPa. a) Temperature when it "escapes" ? b)...
18. ### Magnet Fundamentals and Iron Powder

I am creating a product that incorporates magnetic sensing of magnetic nanoparticles. However due to their cost, I have decided to search for other avenues of testing. My question is about whether Iron Powder will retain a magnetic field once magnetized. I basically will place some iron powder...
19. ### Sample preparation of powders for trace metal analysis

When preparing a fine powder for trace metal analysis, is ashing prior to digesting unnecessary? If not, or not necessarily, where could I learn more about important considerations to determine whether of not any preparation prior to digestion is required? The one instance I have come across...
20. ### Does cacao powder form another "state of matter"?

In another forum someone states that "cacao powder" cannot be considered as a "solid state" since "it cannot sustain shear stresses". Has this statement any basis? -- lightarrow
21. ### What is this old bottle of 'Uranium' found at my workplace?

I was wondering if anyone could give me some insight as to what I found at my work the other day. We have old chemicals (some REALLY old) that turn up in random cabinets from time to time, and this time I was a bottle with a mostly-decayed label where the only thing that could be read was...
22. ### Magnetic powder in a solenoid - how would it react?

Suppose I have a plastic tube about 70% full with magnetic powder, with a copper coil solenoid around the cylinder. By "magnetic powder" I mean each particle is actually a tiny permanent magnet with its own magnetic field. - like you can see in this video When there is no externally applied...
23. ### PXRD Pattern Analysis of Metal Oxide Samples

What benefit is gained for doing more than one measurement on a metal oxide sample with a beamline set up so that the wavelength from a Si 111 monochromator was 0.7 A to obtain a PXRD pattern and then changing the wavelength to 0.8 A to obtain a second PXRD pattern?
24. ### Understanding FWHM in XRD Analysis of Powder Patterns

Why is FWHM taken for calculations in XRD analysis of powder pattern? I mean, why don't we take the full peak value?
25. ### Electrostatic Precipitator to Contain Graphite Powder

Hi all! This is my first post here and I really hope you guys can help! I am currently in senior design at Purdue Fort Wayne in the MET department. I also own a company called Graphite Customs where we make graphite molds for glass blowers. When machining graphite, the powder is very abrasive...
26. ### How can powder resistivity be measured with 4-point probe?

I am studying on Fe powder samples. I have used I-V measurement system to get resistivty. However, I would like to measure with 4-point probe. but I am confused how to prepare the powder sample for 4-point probe. could you tell me there is a way?
27. ### How to build something to vacuum and convey concrete powder

Need to move some concrete powder, would like to use compressed air or a blower. I will need it to vacuum and convey the product, the storage vessel is broken and there is no way to gravity or manually feed it. The vertical distance is 8-10' and no more then 20' horizontal. I have played around...
28. ### Is there a type of powder that can attach to iron objects like a magnet?

Does any kind of magnetic powder exist? I mean not iron powder, that is attracted to a magnet but vice versa, a type of powder, that when i take an iron nail or screw and get it close to that powder, the powder will attach itself to that iron object and stay there, for as long as it is not taken...
29. ### What are the properties of ferromagnetic powder?

Hello! I am trying to understand a few properties of the ferromagnetic powder.I could not get the answers to these questions on the web, since any kind of phrasing i used, popped up search results that related to iron powder or ferromagnetic powder, which are manipulated and shape-shift using...
30. ### Understanding Surface Area: Foldings, Invaginations, Roughness & Powder

why surface area increases with foldings ,invaginations,roughness and powdered form?please someone explain concept of surface area. what is difference between perimeter or (circumference in case of circle)and surface area? Mentor Note: Two posts have been merged.
31. ### Making a Compact Bicycle with Powder Clutches

Hi there. I have a project I am working on now which is kind of like a bicycle which uses powder clutches. The main goal is to make the whole thing compact by reducing the use of shafts. My initial idea of part of the mechanism is in the picture below. I was planning on...
32. ### Granules from fine powder: Agglomaration

I'm trying to convert a fine powder into hard granules (1mm - 3mm dia) & was trying to use a Fluidized Bed Dryer to do it. It seems to somewhat work but the granules stay crumbly & soft rather than the hard product I need. My protocol is to mix ~20% starch as a binder & then add water &...
33. ### Determining Type of Lattice from Powder Diffraction

Homework Statement In a powder diffraction measurement, we obtain a measure of Bragg angles θ. (A powder sample contains small crystallines with all possible random orientations.) In a particular experiment with Al powder, the following data is obtained when X-ray radiation with wavelength λ =...
34. ### Does metal powder in water disperse when water is being charged?

Does metal powder in water disperse when water is being electrically charged? I think that it might not disperse since water is also charged, the repulsion of water molecule will force it back making net repulsion equal to zero. Am I correct? Thanks for answering. Here is the diagram that I...
35. ### How to interpret the powder diffraction?

Hi, I have tried to understand powder diffraction "spectrum". What I do understand is that those diffraction peaks are peaks from ewalds sphere. What I don't understand is how one can get planes and (3d) base vectors out of that. I would really appreciate some help?
36. ### Powder Injection Molding, Binders

Hi, I was just curious, I needed verification, I am reading up on PIM process and I see they use "binders" to keep the shape of the powders before sintering, anyways as I've been reading the binder consists of a surfactant, a filler and a backbone, I was just curious as to what ratios are there...
37. ### Pulse powder delivery of 0.25mg for a few seconds

Hi, I am trying to create a laboratory scale system, where I would like to deliver 0.25 mg of a substance which is granular and powder like consistency. I would like to pulse it for a few seconds and stop it. Can anybody tell me a good delivery mechanism for this. I have a method to disperse...
38. ### Why A Silica Powder Is Melting But Not Burnt When Heated?

Why a silica powder is melting but not burnt when heated? Thank you
39. ### Turning Brown Silica Gravel Into White Silica Powder

This is the silica gravel that I already own: http://images-en.busytrade.com/174645700/Silica-Sand.jpg If I compare to the other silica form such as below silica powder: http://whitefieldminerals.com/documents/product/170e23da48aa40aca37e3a62b3f92023_12.jpg"]silica[/PLAIN] powder...
40. ### Where Are the First Five Intensity Maxima for Copper in a Powder Diffractogram?

Hi everyone Homework Statement I want to make a powder diffractogram of copper. Where do I expect the first five intensity maximums when the used wavelength is lambda=0,711 *10^-10 m Homework Equations Bragg equation 2d sin(omega)=m*lambda The Attempt at a Solution I...
41. ### A simple experiment to determine an unknown powder

Homework Statement You are given a white powder and it could be one of six substances: calcium carbonate, calcium sulfate, sodium hydrogen carbonate, sodium carbonate, sodium chloride and sodium hydroxide. Determine the unknown sample. Materials: White powder (5g) Phenolphthalein Silver...
42. ### Can Fine Iron Powder Be Compressed into a Solid Puck Without Heat or Binders?

I was just curious if it would be possible to compress fine iron powder into a solid puck without applying any heat or binding chemicals, etc. I'm guessing it would take several tonnes of force? Particle size of powder: about 30 microns
43. ### How to obtain Electrical Characteristics/Model of a lump of Powder ?

How to obtain Electrical Characteristics/Model of a lump of Powder ?? Dear All, I have some powder given to us by a chemical engineer. Now, i lumped this in a syringe and connected wires on both sides. Can you give me an idea of an experiment that I can conduct to provide me with the...
44. ### Sodium bicarb AND citric acid powder?

Ok, quick question. I know that baking soda is great for heartburn, but why is it in certain medicines, they have sodium bicarb AND citric acid powder? My wife actually uses those two compounds to make bath fizzies. She adds esentual oils to them for health benefits and smells. haha. Anyway...
45. ### Temperature generated from crushing metal into powder

Say I have a brittle metal that I start smashing up with a hammer to crush it into a powder. How do I know how much the material's temperature will rise from this if I assume an average repetitive force crushing onto 5 grams of the material?
46. ### Black Powder Combustion: Balanced Chemical Equations with State Symbols

I have to write two balanced chemical equations for two reactions, including the state symbols. By knowing that Black Powder is a mixture of solid potassium nitrate (KNO3), sulfur (S) powder and carbon (C), in the form of charcoal, one possible reaction occurring during the combustion of...
47. ### Safe Flea Powder for Dogs - Ingredients & Effects

I'm making a flea powder for my Golden Retriever and hope to find a 'food grade' inert that will disable fleas but not hurt my dog if he licks it off his fur. Potassium sorbate Corn gluten meal Putrescent whole egg solids Corn oil Sesame (includes ground sesame plant) Eugenol...
48. ### Powder Metallurgy - Metal Injection Molding Equipment Sourcing

Hi Everyone, We are an Engineering & Services Company mainly working for Power Generations in industrial field, now we have decided to work in powder metallurgy especially in metal injection molding field, for this purpose we need information about the technology & equipment used in this...
49. ### Powder activated carbon transfer method

Hi, I'm going to school for mechanical engineering and I am interning at a water filtration company. I always come here for help on hw, and I see it as a good source of using my references available, so why not come for real life problems too? Here is the situation: I need to transfer...
50. ### Powder XRD FCC spirals explanation

Hello All, I've been reading about XRD and found this picture online: http://en.wikipedia.org/wiki/File:Aluminumpowderpattern.png My question, which might be due to the lack of background as I'm an ECE guy, is why are the FCC lattice vectors depicted of Spirals whose minima lie on the...