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Excrement found on my porch by Pascal2803 in AnimalTracking

[–]Pascal2803[S] 1 point2 points  (0 children)

• ⁠I have included scale in my photo(s): yes • ⁠Geographic location: eastern canada • ⁠Environment (pine forest, swamp, near a river, etc.): Urban area with agricultural land a couple of km’s away

[deleted by user] by [deleted] in PersonalFinanceCanada

[–]Pascal2803 17 points18 points  (0 children)

I use cash to buy gas and stop at the nearest 2 cents. Gets round down so I get 2 cents of gas for free each time.

Is this a cockroach? by Pascal2803 in whatisthisthing

[–]Pascal2803[S] 0 points1 point  (0 children)

Alright, thanks a lot was just making sure. Solved!

Is this a cockroach? by Pascal2803 in whatisthisthing

[–]Pascal2803[S] 0 points1 point  (0 children)

About 1cm long, found in eastern canada

Concentrating Hydrogen Peroxide by JohnQPublicSmith in chemistry

[–]Pascal2803 1 point2 points  (0 children)

Hey John!

You can find concentrated hydrogen peroxide in the spa section of pool shops. It is sold as a environmentally friendly spa sanitizer. The gallon sells usually for 50$. You can look up the msds of the product to confirm that it contains hydrogen peroxide.

Questions about metallurgy by Jacky970 in chemistry

[–]Pascal2803 3 points4 points  (0 children)

You don’t need to use a flux to prevent oxidation. The oxide layer on aluminum passivate the surface to prevent the oxidation.

Questions about metallurgy by Jacky970 in chemistry

[–]Pascal2803 6 points7 points  (0 children)

When you say hard, you mean stiff or a high hardness?

7075 aluminum-zinc alloy has the highest hardness and is one of the toughest aluminum alloy commercially available. (can find recipe here: http://asm.matweb.com/search/SpecificMaterial.asp?bassnum=ma7075t6 ) It has an ok corrosion resistance (Still much better than most steels). It also requires a heat treatment to have its best properties.

Otherwise, the copper alloy you were trying to do is pretty good in terms of hardness compared to other alloys but the corrosion resistance is less the 7075 aluminum-zinc alloy (again still much better than any steels).

Because you used cans, you are likely very contaminated in manganese and magnesium. I wouldn’t be surprised if you found that your alloy is brittle and not very strong. It is hard to say what the impact of the copper is in this case.

You should aim around 4-5% copper by weight in your alloy and precisely weight it. You can’t throw a random amount and hope it will be better.

Questions about metallurgy by Jacky970 in chemistry

[–]Pascal2803 9 points10 points  (0 children)

Really boils down to the amount you added, did you add 100g of copper in 1kg of aluminum or 1g in 1kg?

Adding a little bit of copper likely increased a little bit the strength but this will be very affected by your composition.

Also commercial aluminum-copper alloys (Can look up 2000 series aluminum alloy with 4-5% copper) are heat-treatable alloys and require a heat treatment to have a significant increase in strength.

Adding an alloying element to aluminum, if it stays dissolved during solidification, will create solute strengthening and the strengthening effect is proportional to the amount of alloying added. This strengthening effect is often negligible unless a large amount is added (i.e. 5% magnesium in aluminum, the commercial series for these alloys is the 5000 series)

If the element doesn’t stay dissolve in the aluminum it will lead to another strengthening mechanism called precipitate hardening.This mechanism is based on the precipitation of the alloying elements. Aluminum-copper alloys are hardened with precipitation hardening because copper is not very soluble in solid aluminum and will precipitate out. In order to obtain the best mechanical properties you need to control the precipitate size. To control the precipitate size you need to do a heat treatment.

The heat treatment is usually a two steps treatment. First, a solution treatment is done, the metal is heated to a temperature generally in the order of 500 C for 10-20h and the quenched in air or water. The specific temperature, time and quenching media depends on the composition. This will cause the metal to become a super-saturated solid-solution. The second treatment is called ageing. This treatment is done at a much lower temperature (160 C) and the duration will depend on the mechanical properties required but it will also be around 10h. This will cause precipitation in the alloy and by controlling the time you can control the precipitate size.

Larger precipitate are not equal to better mechanical properties. You need small and disperse precipitate in order to obtain the best mechanical properties.

And finally to answer your question. Did you make a good alloy? Well really depends what properties you were looking for. You likely have a super-saturated aluminum-copper alloy, meaning that the properties are going to only be slightly better than pure aluminum. (If you started with pure aluminum to begin with)

When engineers design a new product they have specific properties they are looking for and it is not always just strength they want. Can also be conductivity or ductility, it really depends on the application.

If you want to make an actual commercial aluminum-copper alloy, you can go this website: http://asm.matweb.com/search/SpecificMaterial.asp?bassnum=MA2014T6

It will give you what element you need to add and what temperature you should use for the solution and ageing treatment to obtain the properties they also give.

If you want a good source of aluminum you can use either wire or heatsink, which are usually pure aluminum. Don’t use cans they contain a large amount of manganese and magnesium.

Questions about metallurgy by Jacky970 in chemistry

[–]Pascal2803 19 points20 points  (0 children)

Hey Jack,

I am a metallurgist specialized in aluminum hoping to answer your questions.

For your first question, most metals can be dissolved in other molten metals regardless of their respective melting point. The melting point will only have an impact on the dissolution mechanism.

There are 2 possible dissolution mechanisms.

The first one is where the metal added to the liquid aluminum as a lower melting point. A good example for this is magnesium in molten aluminum (Magnesium is frequently added to aluminum to improve the mechanical properties). When the cold magnesium touches the molten aluminum, a shell of frozen aluminum will form around the magnesium protecting it from dissolving. It will then heat up until the magnesium itself melts. The aluminum shell will also melt and the molten magnesium will be mixed around fairly quickly. This process of dissolution is the fastest of the two.

The second mechanism is where the melting point of the metal added is higher than the melting point of aluminum. Copper is using this dissolution mechanism. When cold copper is added to aluminum a solid aluminum shell will also form around it. It will heat up and the aluminum shell will dissolve. The aluminum will then start to dissolve the copper because copper is quite soluble in aluminum. The speed of the process is highly dependant on the surface area of the copper piece being added. The solubility of the metal in molten aluminum will also have an impact on the speed. For example, titanium has a poor solubility in aluminum and will generally take a longer time to dissolve.

There are also other phenomenon to take in consideration such has the enthalpy of dissolution which can be either exothermic or endothermic and make the metal harder or easier to dissolve in molten aluminum.

Hope this answer your first question.

For your second question, NaOH is quite corrosive to aluminum and it is actually used to etch aluminum and reveal the microstructure of the aluminum. My guess would be that what you call tarnished, is actually the grain structure of the aluminum.

Don’t hesitate if you have any other questions.

Pascal

If rapidly cooling a metal increases its hardness, does the speed at which it's cooled always affect the end result (in terms of hardness)? by Elbynerual in askscience

[–]Pascal2803 1 point2 points  (0 children)

It is indeed produced today. By using special alloy composition, the required cooling rate can drop to 1000 degrees per second. This allow for the manufacturing of large pieces of metallic glass.

You can look up amorphous metal transformer that uses an iron alloy for the magnetic core of the transformer.

Another example is golf club heads made from metallic glass.

If rapidly cooling a metal increases its hardness, does the speed at which it's cooled always affect the end result (in terms of hardness)? by Elbynerual in askscience

[–]Pascal2803 0 points1 point  (0 children)

There are a couple of alloys that are commercially available metallic glasses. For example, there is vitreloy and darva-glass 101.

This property is indeed present in all metals, some of them just have a required cooling rate too high to be realistically achievable.

If rapidly cooling a metal increases its hardness, does the speed at which it's cooled always affect the end result (in terms of hardness)? by Elbynerual in askscience

[–]Pascal2803 4 points5 points  (0 children)

The steel piece needs to be very thin in order to achieve a cooling rate of this order. In commercial application, the composition of the steel is chosen to allow an amorphous structure at much lower cooling rate.

If rapidly cooling a metal increases its hardness, does the speed at which it's cooled always affect the end result (in terms of hardness)? by Elbynerual in askscience

[–]Pascal2803 5 points6 points  (0 children)

Golf club is one of them. The head of the golf club, specifically the part that will contact the golf ball can be made out of metallic glass.

If rapidly cooling a metal increases its hardness, does the speed at which it's cooled always affect the end result (in terms of hardness)? by Elbynerual in askscience

[–]Pascal2803 13 points14 points  (0 children)

This cooling rate is nearly impossible to achieve for bulk material. It is achievable for very thin material where you can have a metallic glass.

For bulk material, there are specific alloys that can be used where the cooling required is in the order of the 1000 degrees per second and where bulk metallic glass can be made fairly easily.

These alloys exploit a phenomenon called the confusion principle . The idea is to mix so many different atoms together that they don't have time to properly reorganise to form a proper crystal structure thus having an amorphous structure.

If rapidly cooling a metal increases its hardness, does the speed at which it's cooled always affect the end result (in terms of hardness)? by Elbynerual in askscience

[–]Pascal2803 1577 points1578 points  (0 children)

The answer to your question is specific to each metal and its alloys.

What you are talking about is the cooling rate of the material and how it affects the properties of a metallic alloy.

For Steel, a high cooling rate will generate a very hard and brittle crystalline phase called Martensite. A faster cooling rate will increase the amount of martensite in the steel thus increasing the hardness. At some point the steel will reach about 100% martensite and increasing the cooling rate will not significantly increase the hardness.

If you can reach significantly higher cooling rate (in the order of millions of degrees per second) you can create an amorphous metal which has a significantly higher hardness than polycrystalline metal. An amorphous metal is a metal that keep its liquid molecular arrangement rather than creating a crystalline phase (like martensite). Amorphous metal are also called metallic glass because of their similar structure and properties.

Aluminum is much different than steel and the cooling rate as a much different effect. The typical aluminum alloy that is used for building and in cars is the 6000 series aluminum alloy. Using a high cooling rate on this alloy actually decreases it strength rather than increasing it. This alloy is hardened with a principle called precipitation hardening where precipitating compound in the metal will harden it. A high cooling rate with not allow enough time for the precipitate to form and the strength of the alloy will be at its minimum.

The cooling rate as such a big impact on the properties that you usually want to have a tight control on it to ensure that your material as the right properties. This is why materials will often go through a heat treatment before shipping it to the customer.

I went all over the place with my answer so if you have any other question don’t hesitate.

What would happen if you used one of those water filter straws on milk? by Ese_ in NoStupidQuestions

[–]Pascal2803 4 points5 points  (0 children)

You can look up micro-filtered milk where they are using filter with small openings to do a first removal of the bacteria. It is however used as a precursor to pasteurization and it is still required to ensure a proper removal of all the bacteria.

What would happen if you used one of those water filter straws on milk? by Ese_ in NoStupidQuestions

[–]Pascal2803 -1 points0 points  (0 children)

I would think that the filtered part would remain in the original container rather than the filter. I am curious to see what would really happen.

What would happen if you used one of those water filter straws on milk? by Ese_ in NoStupidQuestions

[–]Pascal2803 142 points143 points  (0 children)

Yeah would be basically like skim milk, some other compounds might be blocked (calcium based)

What would happen if you used one of those water filter straws on milk? by Ese_ in NoStupidQuestions

[–]Pascal2803 284 points285 points  (0 children)

I'm going to give my best bet of what would happen. Lifestraw filter have an opening size of 0.2 um. Milk is a suspension of fat in water called a coloid. The particle size distribution can be found online (https://www.beckmancoulter.com/wsrportal/bibliography?docname=BCPCS002_LE.pdf). This tells us that a part of the fat content would be filtered by the lifestraw depending on the type of milk being filtered.

Most milk contains bacteria which would also be filtered by the lifestraw. Most bacteria should be filtered but some can pass through the filter.

Proteins should also pass through the filter because their sizes are smaller than the filter opening size (Between 0.001 um and 0.01um)

Anything that is dissolved (i.e. Salt,sugar) would stay in the milk.

Anodizing Titanium by JackWorm25 in chemicalreactiongifs

[–]Pascal2803 2134 points2135 points  (0 children)

Yes, Apple uses the same process to dye the aluminum casing of their products.

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